<?xml version="1.0" encoding="us-ascii"?>
<!--XBRL document created with Toppan Merrill Bridge  9.6.7713.40453 -->
<!--Based on XBRL 2.1-->
<!--Created on: 3/8/2021 1:13:58 PM-->
<!--Modified on: 3/8/2021 1:13:58 PM-->
<linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DocumentDocumentAndEntityInformation" roleURI="http://www.ardelyx.com/role/DocumentDocumentAndEntityInformation" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#StatementBalanceSheets" roleURI="http://www.ardelyx.com/role/StatementBalanceSheets" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#StatementBalanceSheetsParenthetical" roleURI="http://www.ardelyx.com/role/StatementBalanceSheetsParenthetical" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#StatementStatementsOfOperationsAndComprehensiveLoss" roleURI="http://www.ardelyx.com/role/StatementStatementsOfOperationsAndComprehensiveLoss" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#StatementStatementsOfStockholdersEquity" roleURI="http://www.ardelyx.com/role/StatementStatementsOfStockholdersEquity" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#StatementStatementsOfCashFlows" roleURI="http://www.ardelyx.com/role/StatementStatementsOfCashFlows" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureOrganizationAndBasisOfPresentation" roleURI="http://www.ardelyx.com/role/DisclosureOrganizationAndBasisOfPresentation" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureSummaryOfSignificantAccountingPolicies" roleURI="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPolicies" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCashAndInvestments" roleURI="http://www.ardelyx.com/role/DisclosureCashAndInvestments" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureFairValueMeasurements" roleURI="http://www.ardelyx.com/role/DisclosureFairValueMeasurements" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureDerivativeLiability" roleURI="http://www.ardelyx.com/role/DisclosureDerivativeLiability" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureBorrowings" roleURI="http://www.ardelyx.com/role/DisclosureBorrowings" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureStockholdersEquity" roleURI="http://www.ardelyx.com/role/DisclosureStockholdersEquity" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureEquityIncentivePlans" roleURI="http://www.ardelyx.com/role/DisclosureEquityIncentivePlans" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosurePropertyAndEquipment" roleURI="http://www.ardelyx.com/role/DisclosurePropertyAndEquipment" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureAccruedExpensesAndOtherCurrentLiabilities" roleURI="http://www.ardelyx.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilities" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureLeases" roleURI="http://www.ardelyx.com/role/DisclosureLeases" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCollaborationAndLicensingAgreements" roleURI="http://www.ardelyx.com/role/DisclosureCollaborationAndLicensingAgreements" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureIncomeTaxes" roleURI="http://www.ardelyx.com/role/DisclosureIncomeTaxes" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureGeographicInformationAndConcentrations" roleURI="http://www.ardelyx.com/role/DisclosureGeographicInformationAndConcentrations" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureNetLossPerShare" roleURI="http://www.ardelyx.com/role/DisclosureNetLossPerShare" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCommitmentsAndContingencies" roleURI="http://www.ardelyx.com/role/DisclosureCommitmentsAndContingencies" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureSelectedQuarterlyFinancialDataUnaudited" roleURI="http://www.ardelyx.com/role/DisclosureSelectedQuarterlyFinancialDataUnaudited" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureSummaryOfSignificantAccountingPoliciesPolicies" roleURI="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCashAndInvestmentsTables" roleURI="http://www.ardelyx.com/role/DisclosureCashAndInvestmentsTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureFairValueMeasurementsTables" roleURI="http://www.ardelyx.com/role/DisclosureFairValueMeasurementsTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureDerivativeLiabilityTables" roleURI="http://www.ardelyx.com/role/DisclosureDerivativeLiabilityTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureBorrowingsTables" roleURI="http://www.ardelyx.com/role/DisclosureBorrowingsTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureEquityIncentivePlansTables" roleURI="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosurePropertyAndEquipmentTables" roleURI="http://www.ardelyx.com/role/DisclosurePropertyAndEquipmentTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureAccruedExpensesAndOtherCurrentLiabilitiesTables" roleURI="http://www.ardelyx.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureLeasesTables" roleURI="http://www.ardelyx.com/role/DisclosureLeasesTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCollaborationAndLicensingAgreementsTables" roleURI="http://www.ardelyx.com/role/DisclosureCollaborationAndLicensingAgreementsTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureIncomeTaxesTables" roleURI="http://www.ardelyx.com/role/DisclosureIncomeTaxesTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureGeographicInformationAndConcentrationsTables" roleURI="http://www.ardelyx.com/role/DisclosureGeographicInformationAndConcentrationsTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureNetLossPerShareTables" roleURI="http://www.ardelyx.com/role/DisclosureNetLossPerShareTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCommitmentsAndContingenciesTables" roleURI="http://www.ardelyx.com/role/DisclosureCommitmentsAndContingenciesTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureSelectedQuarterlyFinancialDataUnauditedTables" roleURI="http://www.ardelyx.com/role/DisclosureSelectedQuarterlyFinancialDataUnauditedTables" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureOrganizationAndBasisOfPresentationAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosureOrganizationAndBasisOfPresentationAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureSummaryOfSignificantAccountingPoliciesPriorPeriodErrorsDetails" roleURI="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPriorPeriodErrorsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureSummaryOfSignificantAccountingPoliciesCumulativeAdjustmentsDetails" roleURI="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesCumulativeAdjustmentsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureSummaryOfSignificantAccountingPoliciesLiquidityDetails" roleURI="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesLiquidityDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCashAndInvestmentsScheduleOfSecuritiesClassifiedAsCashAndInvestmentsDetails" roleURI="http://www.ardelyx.com/role/DisclosureCashAndInvestmentsScheduleOfSecuritiesClassifiedAsCashAndInvestmentsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCashAndInvestmentsAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosureCashAndInvestmentsAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCashAndInvestmentsAmortizedCostAndEstimatedFairValueOfAvailableForSaleDebtSecuritiesDetails" roleURI="http://www.ardelyx.com/role/DisclosureCashAndInvestmentsAmortizedCostAndEstimatedFairValueOfAvailableForSaleDebtSecuritiesDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureFairValueMeasurementsSummaryOfFairValueMeasurementsOfCompanySFinancialAssetsAndLiabilitiesDetails" roleURI="http://www.ardelyx.com/role/DisclosureFairValueMeasurementsSummaryOfFairValueMeasurementsOfCompanySFinancialAssetsAndLiabilitiesDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureDerivativeLiabilityAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosureDerivativeLiabilityAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureDerivativeLiabilityScheduleOfChangesInFairValueDetails" roleURI="http://www.ardelyx.com/role/DisclosureDerivativeLiabilityScheduleOfChangesInFairValueDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureBorrowingsDetails" roleURI="http://www.ardelyx.com/role/DisclosureBorrowingsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureStockholdersEquityDetails" roleURI="http://www.ardelyx.com/role/DisclosureStockholdersEquityDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureEquityIncentivePlansAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureEquityIncentivePlansSummaryOfActivityUnder2008Plan2014PlanAndInducementPlanIncludingGrantsToNonemployeesIssuedDetails" roleURI="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansSummaryOfActivityUnder2008Plan2014PlanAndInducementPlanIncludingGrantsToNonemployeesIssuedDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureEquityIncentivePlansSummaryOfNonVestedRsuActivityDetails" roleURI="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansSummaryOfNonVestedRsuActivityDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureEquityIncentivePlansSummaryOfWeightedAverageAssumptionsToEstimateFairValueOfEmployeeStockOptionsDetails" roleURI="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansSummaryOfWeightedAverageAssumptionsToEstimateFairValueOfEmployeeStockOptionsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureEquityIncentivePlansEmployeeStockPurchasePlanDetails" roleURI="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansEmployeeStockPurchasePlanDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureEquityIncentivePlansSummaryOfStockBasedCompensationExpenseRecognizedDetails" roleURI="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansSummaryOfStockBasedCompensationExpenseRecognizedDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureEquityIncentivePlansUnrecognizedStockBasedCompensationDetails" roleURI="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansUnrecognizedStockBasedCompensationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosurePropertyAndEquipmentSummaryOfPropertyAndEquipmentDetails" roleURI="http://www.ardelyx.com/role/DisclosurePropertyAndEquipmentSummaryOfPropertyAndEquipmentDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosurePropertyAndEquipmentAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosurePropertyAndEquipmentAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureAccruedExpensesAndOtherCurrentLiabilitiesScheduleOfAccruedLiabilitiesAndOtherLiabilitiesDetails" roleURI="http://www.ardelyx.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesScheduleOfAccruedLiabilitiesAndOtherLiabilitiesDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureLeasesDetails" roleURI="http://www.ardelyx.com/role/DisclosureLeasesDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureLeasesBalanceSheetAndStatementOfOperationsDetails" roleURI="http://www.ardelyx.com/role/DisclosureLeasesBalanceSheetAndStatementOfOperationsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureLeasesUndiscountedCashPaymentObligationsDetails" roleURI="http://www.ardelyx.com/role/DisclosureLeasesUndiscountedCashPaymentObligationsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCollaborationAndLicensingAgreementsAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosureCollaborationAndLicensingAgreementsAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureIncomeTaxesDetails" roleURI="http://www.ardelyx.com/role/DisclosureIncomeTaxesDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureIncomeTaxesReconciliationOfStatutoryFederalIncomeTaxRateToCompanySEffectiveTaxRateDetails" roleURI="http://www.ardelyx.com/role/DisclosureIncomeTaxesReconciliationOfStatutoryFederalIncomeTaxRateToCompanySEffectiveTaxRateDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureIncomeTaxesSignificantComponentsOfCompanySDeferredTaxAssetsDetails" roleURI="http://www.ardelyx.com/role/DisclosureIncomeTaxesSignificantComponentsOfCompanySDeferredTaxAssetsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureIncomeTaxesAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosureIncomeTaxesAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureIncomeTaxesReconciliationOfBeginningAndEndingAmountOfUnrecognizedTaxBenefitsDetails" roleURI="http://www.ardelyx.com/role/DisclosureIncomeTaxesReconciliationOfBeginningAndEndingAmountOfUnrecognizedTaxBenefitsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureGeographicInformationAndConcentrationsDetails" roleURI="http://www.ardelyx.com/role/DisclosureGeographicInformationAndConcentrationsDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureGeographicInformationAndConcentrationsConcentrationRiskDetails" roleURI="http://www.ardelyx.com/role/DisclosureGeographicInformationAndConcentrationsConcentrationRiskDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureNetLossPerShareComputationOfBasicAndDilutedLossPerShareAttributableToCommonStockholdersDetails" roleURI="http://www.ardelyx.com/role/DisclosureNetLossPerShareComputationOfBasicAndDilutedLossPerShareAttributableToCommonStockholdersDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureNetLossPerShareAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosureNetLossPerShareAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureCommitmentsAndContingenciesAdditionalInformationDetails" roleURI="http://www.ardelyx.com/role/DisclosureCommitmentsAndContingenciesAdditionalInformationDetails" />
  <roleRef xlink:type="simple" xlink:href="ardx-20201231.xsd#DisclosureSelectedQuarterlyFinancialDataUnauditedScheduleOfSelectedQuarterlyFinancialResultsFromOperationsDetails" roleURI="http://www.ardelyx.com/role/DisclosureSelectedQuarterlyFinancialDataUnauditedScheduleOfSelectedQuarterlyFinancialResultsFromOperationsDetails" />
  <presentationLink xlink:role="http://www.ardelyx.com/role/DocumentDocumentAndEntityInformation" xlink:type="extended" xlink:title="00090 - Document - Document and Entity Information">
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CoverAbstract" xlink:label="dei_CoverAbstract" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentInformationTable" xlink:label="dei_DocumentInformationTable_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_CoverAbstract" xlink:to="dei_DocumentInformationTable_637508060358800245" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressesAddressTypeAxis" xlink:label="dei_EntityAddressesAddressTypeAxis_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationTable_637508060358800245" xlink:to="dei_EntityAddressesAddressTypeAxis_637508060358800245" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_AddressTypeDomain" xlink:label="dei_AddressTypeDomain_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_EntityAddressesAddressTypeAxis_637508060358800245" xlink:to="dei_AddressTypeDomain_637508060358800245" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_OtherAddressMember" xlink:label="dei_OtherAddressMember_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_AddressTypeDomain_637508060358800245" xlink:to="dei_OtherAddressMember_637508060358800245" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentInformationLineItems" xlink:label="dei_DocumentInformationLineItems_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationTable_637508060358800245" xlink:to="dei_DocumentInformationLineItems_637508060358800245" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentType" xlink:label="dei_DocumentType_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_DocumentType_637508060358800245" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentAnnualReport" xlink:label="dei_DocumentAnnualReport_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_DocumentAnnualReport_637508060358800245" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="dei_DocumentPeriodEndDate_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_DocumentPeriodEndDate_637508060358800245" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentTransitionReport" xlink:label="dei_DocumentTransitionReport_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_DocumentTransitionReport_637508060358800245" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityFileNumber" xlink:label="dei_EntityFileNumber_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityFileNumber_637508060358800245" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityRegistrantName" xlink:label="dei_EntityRegistrantName_637508060358800245" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityRegistrantName_637508060358800245" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityIncorporationStateCountryCode" xlink:label="dei_EntityIncorporationStateCountryCode_637508060358810246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityIncorporationStateCountryCode_637508060358810246" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityTaxIdentificationNumber" xlink:label="dei_EntityTaxIdentificationNumber_637508060358810246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityTaxIdentificationNumber_637508060358810246" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressAddressLine1" xlink:label="dei_EntityAddressAddressLine1_637508060358810246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityAddressAddressLine1_637508060358810246" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressAddressLine2" xlink:label="dei_EntityAddressAddressLine2_637508060358810246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityAddressAddressLine2_637508060358810246" order="10" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressCityOrTown" xlink:label="dei_EntityAddressCityOrTown_637508060358810246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityAddressCityOrTown_637508060358810246" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressStateOrProvince" xlink:label="dei_EntityAddressStateOrProvince_637508060358820754" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityAddressStateOrProvince_637508060358820754" order="12" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityAddressPostalZipCode" xlink:label="dei_EntityAddressPostalZipCode_637508060358820754" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityAddressPostalZipCode_637508060358820754" order="13" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CityAreaCode" xlink:label="dei_CityAreaCode_637508060358820754" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_CityAreaCode_637508060358820754" order="14" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_LocalPhoneNumber" xlink:label="dei_LocalPhoneNumber_637508060358820754" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_LocalPhoneNumber_637508060358820754" order="15" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_Security12bTitle" xlink:label="dei_Security12bTitle_637508060358820754" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_Security12bTitle_637508060358820754" order="16" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_TradingSymbol" xlink:label="dei_TradingSymbol_637508060358820754" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_TradingSymbol_637508060358820754" order="17" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="8" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_SecurityExchangeName" xlink:label="dei_SecurityExchangeName_637508060358820754" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_SecurityExchangeName_637508060358820754" order="18" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityWellKnownSeasonedIssuer" xlink:label="dei_EntityWellKnownSeasonedIssuer_637508060358820754" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityWellKnownSeasonedIssuer_637508060358820754" order="19" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityVoluntaryFilers" xlink:label="dei_EntityVoluntaryFilers_637508060358820754" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityVoluntaryFilers_637508060358820754" order="20" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCurrentReportingStatus" xlink:label="dei_EntityCurrentReportingStatus_637508060358830299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityCurrentReportingStatus_637508060358830299" order="21" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityInteractiveDataCurrent" xlink:label="dei_EntityInteractiveDataCurrent_637508060358830299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityInteractiveDataCurrent_637508060358830299" order="22" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityFilerCategory" xlink:label="dei_EntityFilerCategory_637508060358830299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityFilerCategory_637508060358830299" order="23" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntitySmallBusiness" xlink:label="dei_EntitySmallBusiness_637508060358830299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntitySmallBusiness_637508060358830299" order="24" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityEmergingGrowthCompany" xlink:label="dei_EntityEmergingGrowthCompany_637508060358830299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityEmergingGrowthCompany_637508060358830299" order="25" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IcfrAuditorAttestationFlag" xlink:label="ardx_IcfrAuditorAttestationFlag_637508060358830299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="ardx_IcfrAuditorAttestationFlag_637508060358830299" order="26" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityShellCompany" xlink:label="dei_EntityShellCompany_637508060358830299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityShellCompany_637508060358830299" order="27" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityPublicFloat" xlink:label="dei_EntityPublicFloat_637508060358840251" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityPublicFloat_637508060358840251" order="28" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="dei_EntityCommonStockSharesOutstanding_637508060358840251" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityCommonStockSharesOutstanding_637508060358840251" order="29" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="dei_EntityCentralIndexKey_637508060358840251" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_EntityCentralIndexKey_637508060358840251" order="30" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="dei_CurrentFiscalYearEndDate_637508060358840251" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_CurrentFiscalYearEndDate_637508060358840251" order="31" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="dei_DocumentFiscalYearFocus_637508060358840251" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_DocumentFiscalYearFocus_637508060358840251" order="32" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="dei_DocumentFiscalPeriodFocus_637508060358840251" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_DocumentFiscalPeriodFocus_637508060358840251" order="33" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd#dei_AmendmentFlag" xlink:label="dei_AmendmentFlag_637508060358840251" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="dei_DocumentInformationLineItems_637508060358800245" xlink:to="dei_AmendmentFlag_637508060358840251" order="34" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/StatementBalanceSheets" xlink:type="extended" xlink:title="00100 - Statement - BALANCE SHEETS">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="StatementOfFinancialPositionAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="us-gaap_AssetsAbstract_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_AssetsAbstract_637508060358850246" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="us-gaap_AssetsCurrentAbstract_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAbstract_637508060358850246" xlink:to="us-gaap_AssetsCurrentAbstract_637508060358850246" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract_637508060358850246" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_637508060358850246" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract_637508060358850246" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_637508060358850246" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerAssetNetCurrent" xlink:label="us-gaap_ContractWithCustomerAssetNetCurrent_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract_637508060358850246" xlink:to="us-gaap_ContractWithCustomerAssetNetCurrent_637508060358850246" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract_637508060358850246" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_637508060358850246" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="us-gaap_AssetsCurrent_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsCurrentAbstract_637508060358850246" xlink:to="us-gaap_AssetsCurrent_637508060358850246" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAbstract_637508060358850246" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_637508060358850246" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermInvestments" xlink:label="us-gaap_LongTermInvestments_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAbstract_637508060358850246" xlink:to="us-gaap_LongTermInvestments_637508060358850246" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAbstract_637508060358850246" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset_637508060358850246" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="us-gaap_OtherAssetsNoncurrent_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAbstract_637508060358850246" xlink:to="us-gaap_OtherAssetsNoncurrent_637508060358850246" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets_637508060358850246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAbstract_637508060358850246" xlink:to="us-gaap_Assets_637508060358850246" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_LiabilitiesAndStockholdersEquityAbstract_637508060358860300" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="us-gaap_LiabilitiesCurrentAbstract_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract_637508060358860300" xlink:to="us-gaap_LiabilitiesCurrentAbstract_637508060358860300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="us-gaap_AccountsPayableCurrent_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract_637508060358860300" xlink:to="us-gaap_AccountsPayableCurrent_637508060358860300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract_637508060358860300" xlink:to="us-gaap_EmployeeRelatedLiabilitiesCurrent_637508060358860300" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract_637508060358860300" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent_637508060358860300" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LoansPayableCurrent" xlink:label="us-gaap_LoansPayableCurrent_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract_637508060358860300" xlink:to="us-gaap_LoansPayableCurrent_637508060358860300" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredRevenue" xlink:label="us-gaap_DeferredRevenue_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract_637508060358860300" xlink:to="us-gaap_DeferredRevenue_637508060358860300" order="5" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilities" xlink:label="us-gaap_AccruedLiabilitiesAndOtherLiabilities_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract_637508060358860300" xlink:to="us-gaap_AccruedLiabilitiesAndOtherLiabilities_637508060358860300" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesCurrentAbstract_637508060358860300" xlink:to="us-gaap_LiabilitiesCurrent_637508060358860300" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_637508060358860300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract_637508060358860300" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent_637508060358860300" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermLoansPayable" xlink:label="us-gaap_LongTermLoansPayable_637508060358870246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract_637508060358860300" xlink:to="us-gaap_LongTermLoansPayable_637508060358870246" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities_637508060358870246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract_637508060358860300" xlink:to="us-gaap_Liabilities_637508060358870246" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="us-gaap_CommitmentsAndContingencies_637508060358870246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract_637508060358860300" xlink:to="us-gaap_CommitmentsAndContingencies_637508060358870246" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="us-gaap_StockholdersEquityAbstract_637508060358870246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract_637508060358860300" xlink:to="us-gaap_StockholdersEquityAbstract_637508060358870246" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="us-gaap_PreferredStockValue_637508060358870246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract_637508060358870246" xlink:to="us-gaap_PreferredStockValue_637508060358870246" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue_637508060358870246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract_637508060358870246" xlink:to="us-gaap_CommonStockValue_637508060358870246" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_637508060358870246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract_637508060358870246" xlink:to="us-gaap_AdditionalPaidInCapitalCommonStock_637508060358870246" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_637508060358870246" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract_637508060358870246" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit_637508060358870246" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_637508060358880248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract_637508060358870246" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_637508060358880248" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity_637508060358890248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityAbstract_637508060358870246" xlink:to="us-gaap_StockholdersEquity_637508060358890248" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_637508060358890248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract_637508060358860300" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity_637508060358890248" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/StatementBalanceSheetsParenthetical" xlink:type="extended" xlink:title="00105 - Statement - BALANCE SHEETS (Parenthetical)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract" xlink:label="StatementOfFinancialPositionAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_637508060358890248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_PreferredStockParOrStatedValuePerShare_637508060358890248" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="us-gaap_PreferredStockSharesAuthorized_637508060358890248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_PreferredStockSharesAuthorized_637508060358890248" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="us-gaap_PreferredStockSharesIssued_637508060358890248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_PreferredStockSharesIssued_637508060358890248" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="us-gaap_PreferredStockSharesOutstanding_637508060358890248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_PreferredStockSharesOutstanding_637508060358890248" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_CommonStockParOrStatedValuePerShare_637508060358900247" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="us-gaap_CommonStockSharesAuthorized_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_CommonStockSharesAuthorized_637508060358900247" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="us-gaap_CommonStockSharesIssued_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_CommonStockSharesIssued_637508060358900247" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="us-gaap_CommonStockSharesOutstanding_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfFinancialPositionAbstract" xlink:to="us-gaap_CommonStockSharesOutstanding_637508060358900247" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/StatementStatementsOfOperationsAndComprehensiveLoss" xlink:type="extended" xlink:title="00200 - Statement - STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:label="IncomeStatementAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeStatementAbstract" xlink:to="us-gaap_StatementTable_637508060358900247" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="srt_ProductOrServiceAxis_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable_637508060358900247" xlink:to="srt_ProductOrServiceAxis_637508060358900247" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="srt_ProductsAndServicesDomain_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ProductOrServiceAxis_637508060358900247" xlink:to="srt_ProductsAndServicesDomain_637508060358900247" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborativeDevelopmentMember" xlink:label="ardx_CollaborativeDevelopmentMember_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ProductsAndServicesDomain_637508060358900247" xlink:to="ardx_CollaborativeDevelopmentMember_637508060358900247" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProductAndServiceOtherMember" xlink:label="us-gaap_ProductAndServiceOtherMember_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ProductsAndServicesDomain_637508060358900247" xlink:to="us-gaap_ProductAndServiceOtherMember_637508060358900247" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LicenseMember" xlink:label="us-gaap_LicenseMember_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ProductsAndServicesDomain_637508060358900247" xlink:to="us-gaap_LicenseMember_637508060358900247" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable_637508060358900247" xlink:to="us-gaap_StatementLineItems_637508060358900247" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenuesAbstract" xlink:label="us-gaap_RevenuesAbstract_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_RevenuesAbstract_637508060358900247" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RevenuesAbstract_637508060358900247" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_637508060358900247" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="us-gaap_OperatingExpensesAbstract_637508060358900247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_OperatingExpensesAbstract_637508060358900247" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="us-gaap_CostOfRevenue_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingExpensesAbstract_637508060358900247" xlink:to="us-gaap_CostOfRevenue_637508060358910248" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="us-gaap_ResearchAndDevelopmentExpense_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingExpensesAbstract_637508060358900247" xlink:to="us-gaap_ResearchAndDevelopmentExpense_637508060358910248" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="us-gaap_GeneralAndAdministrativeExpense_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingExpensesAbstract_637508060358900247" xlink:to="us-gaap_GeneralAndAdministrativeExpense_637508060358910248" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="us-gaap_CostsAndExpenses_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingExpensesAbstract_637508060358900247" xlink:to="us-gaap_CostsAndExpenses_637508060358910248" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_OperatingIncomeLoss_637508060358910248" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpense" xlink:label="us-gaap_InterestExpense_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_InterestExpense_637508060358910248" order="4" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="8" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="us-gaap_NonoperatingIncomeExpense_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_NonoperatingIncomeExpense_637508060358910248" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_637508060358910248" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_IncomeTaxExpenseBenefit_637508060358910248" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_NetIncomeLoss_637508060358910248" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareBasicAndDiluted" xlink:label="us-gaap_EarningsPerShareBasicAndDiluted_637508060358910248" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_EarningsPerShareBasicAndDiluted_637508060358910248" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" xlink:label="us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_637508060358920247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_637508060358920247" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAbstract" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxAbstract_637508060358920247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358900247" xlink:to="us-gaap_ComprehensiveIncomeNetOfTaxAbstract_637508060358920247" order="11" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_637508060358920247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ComprehensiveIncomeNetOfTaxAbstract_637508060358920247" xlink:to="us-gaap_NetIncomeLoss_637508060358920247" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_637508060358920247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ComprehensiveIncomeNetOfTaxAbstract_637508060358920247" xlink:to="us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_637508060358920247" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="7" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax_637508060358920247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ComprehensiveIncomeNetOfTaxAbstract_637508060358920247" xlink:to="us-gaap_ComprehensiveIncomeNetOfTax_637508060358920247" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/StatementStatementsOfStockholdersEquity" xlink:type="extended" xlink:title="00300 - Statement - STATEMENTS OF STOCKHOLDERS' EQUITY">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementOfStockholdersEquityAbstract" xlink:label="StatementOfStockholdersEquityAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable_637508060358920247" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfStockholdersEquityAbstract" xlink:to="us-gaap_StatementTable_637508060358920247" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="us-gaap_StatementEquityComponentsAxis_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable_637508060358920247" xlink:to="us-gaap_StatementEquityComponentsAxis_637508060358930249" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockMember" xlink:label="us-gaap_CommonStockMember_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis_637508060358930249" xlink:to="us-gaap_CommonStockMember_637508060358930249" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="us-gaap_AdditionalPaidInCapitalMember_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis_637508060358930249" xlink:to="us-gaap_AdditionalPaidInCapitalMember_637508060358930249" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="us-gaap_RetainedEarningsMember_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis_637508060358930249" xlink:to="us-gaap_RetainedEarningsMember_637508060358930249" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis_637508060358930249" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember_637508060358930249" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementEquityComponentsAxis_637508060358930249" xlink:to="us-gaap_EquityComponentDomain_637508060358930249" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable_637508060358920247" xlink:to="us-gaap_SubsidiarySaleOfStockAxis_637508060358930249" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PrivatePlacementMember" xlink:label="us-gaap_PrivatePlacementMember_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis_637508060358930249" xlink:to="us-gaap_PrivatePlacementMember_637508060358930249" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OverAllotmentOptionMember" xlink:label="us-gaap_OverAllotmentOptionMember_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis_637508060358930249" xlink:to="us-gaap_OverAllotmentOptionMember_637508060358930249" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AtMarketOfferingMember" xlink:label="ardx_AtMarketOfferingMember_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis_637508060358930249" xlink:to="ardx_AtMarketOfferingMember_637508060358930249" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis_637508060358930249" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain_637508060358930249" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable_637508060358920247" xlink:to="us-gaap_StatementLineItems_637508060358930249" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockholdersEquity_637508060358930249" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="us-gaap_SharesOutstanding_637508060358930249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_SharesOutstanding_637508060358930249" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:label="us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_637508060358940249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_637508060358940249" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_637508060358940249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_637508060358940249" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="us-gaap_StockIssuedDuringPeriodValueIssuedForServices_637508060358940249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockIssuedDuringPeriodValueIssuedForServices_637508060358940249" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_637508060358940249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_637508060358940249" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_637508060358940249" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_637508060358940249" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_637508060358950251" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_637508060358950251" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_637508060358950251" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_637508060358950251" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_637508060358960250" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_637508060358960250" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_637508060358960250" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_637508060358960250" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="9" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_637508060358960250" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_NetIncomeLoss_637508060358960250" order="12" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_637508060358960250" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockIssuedDuringPeriodValueNewIssues_637508060358960250" order="13" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_637508060358960250" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues_637508060358960250" order="14" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption" xlink:label="us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_637508060358970252" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption_637508060358970252" order="15" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="9" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity_637508060358970252" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_StockholdersEquity_637508060358970252" order="16" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharesOutstanding" xlink:label="us-gaap_SharesOutstanding_637508060358970252" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358930249" xlink:to="us-gaap_SharesOutstanding_637508060358970252" order="17" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/StatementStatementsOfCashFlows" xlink:type="extended" xlink:title="00400 - Statement - STATEMENTS OF CASH FLOWS">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="StatementOfCashFlowsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable_637508060358970252" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="StatementOfCashFlowsAbstract" xlink:to="us-gaap_StatementTable_637508060358970252" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_637508060358970252" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable_637508060358970252" xlink:to="us-gaap_SubsidiarySaleOfStockAxis_637508060358970252" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_637508060358970252" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis_637508060358970252" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain_637508060358970252" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AtMarketOfferingMember" xlink:label="ardx_AtMarketOfferingMember_637508060358970252" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060358970252" xlink:to="ardx_AtMarketOfferingMember_637508060358970252" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems_637508060358970252" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable_637508060358970252" xlink:to="us-gaap_StatementLineItems_637508060358970252" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358970252" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="us-gaap_ProfitLoss_637508060358980305" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Depreciation" xlink:label="us-gaap_Depreciation_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="us-gaap_Depreciation_637508060358980305" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="us-gaap_AmortizationOfFinancingCosts_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="us-gaap_AmortizationOfFinancingCosts_637508060358980305" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AmortizationOfDeferredCompensationExpense" xlink:label="ardx_AmortizationOfDeferredCompensationExpense_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="ardx_AmortizationOfDeferredCompensationExpense_637508060358980305" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:label="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_637508060358980305" order="4" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_NonCashLeaseExpense" xlink:label="ardx_NonCashLeaseExpense_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="ardx_NonCashLeaseExpense_637508060358980305" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="us-gaap_ShareBasedCompensation_637508060358980305" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInDerivativeLiabilities" xlink:label="us-gaap_IncreaseDecreaseInDerivativeLiabilities_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="us-gaap_IncreaseDecreaseInDerivativeLiabilities_637508060358980305" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_NoncashInterestExpense" xlink:label="ardx_NoncashInterestExpense_637508060358980305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="ardx_NoncashInterestExpense_637508060358980305" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IncreaseDecreaseInUnbilledRevenue" xlink:label="ardx_IncreaseDecreaseInUnbilledRevenue_637508060358990258" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" xlink:to="ardx_IncreaseDecreaseInUnbilledRevenue_637508060358990258" order="1" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable_637508060358990258" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" xlink:to="us-gaap_IncreaseDecreaseInAccountsReceivable_637508060358990258" order="2" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_637508060358990258" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" xlink:to="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_637508060358990258" order="3" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayable_637508060358990258" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayable_637508060358990258" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_637508060359000257" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" xlink:to="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_637508060359000257" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IncreaseDecreaseInOperatingLeaseLiabilities" xlink:label="ardx_IncreaseDecreaseInOperatingLeaseLiabilities_637508060359000257" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" xlink:to="ardx_IncreaseDecreaseInOperatingLeaseLiabilities_637508060359000257" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInAccruedLiabilities_637508060359000257" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" xlink:to="us-gaap_IncreaseDecreaseInAccruedLiabilities_637508060359000257" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="us-gaap_IncreaseDecreaseInDeferredRevenue_637508060359000257" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_637508060358990258" xlink:to="us-gaap_IncreaseDecreaseInDeferredRevenue_637508060359000257" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_637508060359000257" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_637508060358980305" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities_637508060359000257" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_637508060359000257" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358970252" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_637508060359000257" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities" xlink:label="us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_637508060359000257" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_637508060359000257" xlink:to="us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_637508060359000257" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireShortTermInvestments" xlink:label="us-gaap_PaymentsToAcquireShortTermInvestments_637508060359000257" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_637508060359000257" xlink:to="us-gaap_PaymentsToAcquireShortTermInvestments_637508060359000257" order="2" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_637508060359010253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_637508060359000257" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_637508060359010253" order="3" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_637508060359010253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_637508060359000257" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities_637508060359010253" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_637508060359010253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358970252" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_637508060359010253" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:label="us-gaap_SaleOfStockConsiderationReceivedOnTransaction_637508060359010253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_637508060359010253" xlink:to="us-gaap_SaleOfStockConsiderationReceivedOnTransaction_637508060359010253" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:label="us-gaap_ProceedsFromIssuanceOfPrivatePlacement_637508060359010253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_637508060359010253" xlink:to="us-gaap_ProceedsFromIssuanceOfPrivatePlacement_637508060359010253" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_637508060359010253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_637508060359010253" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock_637508060359010253" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:label="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_637508060359010253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_637508060359010253" xlink:to="us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_637508060359010253" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RepaymentsOfDebt" xlink:label="us-gaap_RepaymentsOfDebt_637508060359010253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_637508060359010253" xlink:to="us-gaap_RepaymentsOfDebt_637508060359010253" order="5" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromDebtNetOfIssuanceCosts" xlink:label="us-gaap_ProceedsFromDebtNetOfIssuanceCosts_637508060359020253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_637508060359010253" xlink:to="us-gaap_ProceedsFromDebtNetOfIssuanceCosts_637508060359020253" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_637508060359020253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_637508060359010253" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities_637508060359020253" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_637508060359020253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358970252" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_637508060359020253" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_637508060359020253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358970252" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_637508060359020253" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_6375080603590202531" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358970252" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_6375080603590202531" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_637508060359020253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358970252" xlink:to="us-gaap_SupplementalCashFlowInformationAbstract_637508060359020253" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestPaidNet" xlink:label="us-gaap_InterestPaidNet_637508060359020253" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract_637508060359020253" xlink:to="us-gaap_InterestPaidNet_637508060359020253" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxesPaidNet" xlink:label="us-gaap_IncomeTaxesPaidNet_637508060359030254" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract_637508060359020253" xlink:to="us-gaap_IncomeTaxesPaidNet_637508060359030254" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:label="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_637508060359030254" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060358970252" xlink:to="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_637508060359030254" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability" xlink:label="us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_637508060359030254" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_637508060359030254" xlink:to="us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_637508060359030254" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssued1" xlink:label="us-gaap_StockIssued1_637508060359030254" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_637508060359030254" xlink:to="us-gaap_StockIssued1_637508060359030254" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IssuanceOfDerivativeInConnectionWithIssuanceOfLoanPayable" xlink:label="ardx_IssuanceOfDerivativeInConnectionWithIssuanceOfLoanPayable_637508060359030254" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_637508060359030254" xlink:to="ardx_IssuanceOfDerivativeInConnectionWithIssuanceOfLoanPayable_637508060359030254" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureOrganizationAndBasisOfPresentation" xlink:type="extended" xlink:title="10101 - Disclosure - Organization and Basis of Presentation">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock" xlink:label="us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock_637508060359040290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock_637508060359040290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPolicies" xlink:type="extended" xlink:title="10201 - Disclosure - Summary of Significant Accounting Policies">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="AccountingPoliciesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SignificantAccountingPoliciesTextBlock" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock_637508060359040290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_SignificantAccountingPoliciesTextBlock_637508060359040290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCashAndInvestments" xlink:type="extended" xlink:title="10301 - Disclosure - Cash and Investments">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract" xlink:label="CashAndCashEquivalentsAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashAndInvestmentsTextBlock" xlink:label="ardx_CashAndInvestmentsTextBlock_637508060359040290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CashAndCashEquivalentsAbstract" xlink:to="ardx_CashAndInvestmentsTextBlock_637508060359040290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureFairValueMeasurements" xlink:type="extended" xlink:title="10401 - Disclosure - Fair Value Measurements">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueDisclosuresAbstract" xlink:label="FairValueDisclosuresAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueDisclosuresTextBlock" xlink:label="us-gaap_FairValueDisclosuresTextBlock_637508060359050290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="FairValueDisclosuresAbstract" xlink:to="us-gaap_FairValueDisclosuresTextBlock_637508060359050290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureDerivativeLiability" xlink:type="extended" xlink:title="10501 - Disclosure - Derivative Liability">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_637508060359050290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:to="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_637508060359050290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="9" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureBorrowings" xlink:type="extended" xlink:title="10601 - Disclosure - Borrowings">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtDisclosureAbstract" xlink:label="us-gaap_DebtDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtDisclosureTextBlock" xlink:label="us-gaap_DebtDisclosureTextBlock_637508060359050290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtDisclosureAbstract" xlink:to="us-gaap_DebtDisclosureTextBlock_637508060359050290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureStockholdersEquity" xlink:type="extended" xlink:title="10701 - Disclosure - Stockholders' Equity">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityNoteAbstract" xlink:label="us-gaap_StockholdersEquityNoteAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock_637508060359050290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityNoteAbstract" xlink:to="us-gaap_StockholdersEquityNoteDisclosureTextBlock_637508060359050290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureEquityIncentivePlans" xlink:type="extended" xlink:title="10801 - Disclosure - Equity Incentive Plans">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_636737256074065195" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_637508060359050290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_636737256074065195" xlink:to="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_637508060359050290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosurePropertyAndEquipment" xlink:type="extended" xlink:title="10901 - Disclosure - Property and Equipment">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="PropertyPlantAndEquipmentAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_637508060359060274" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PropertyPlantAndEquipmentAbstract" xlink:to="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_637508060359060274" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilities" xlink:type="extended" xlink:title="11001 - Disclosure - Accrued Expenses and Other Current Liabilities">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PayablesAndAccrualsAbstract" xlink:label="PayablesAndAccrualsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock" xlink:label="us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock_637508060359060274" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="us-gaap_AccountsPayableAccruedLiabilitiesAndOtherLiabilitiesDisclosureCurrentTextBlock_637508060359060274" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureLeases" xlink:type="extended" xlink:title="11101 - Disclosure - Leases">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="us-gaap_LeasesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeasesTextBlock" xlink:label="us-gaap_LesseeOperatingLeasesTextBlock_637508060359060274" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeasesAbstract" xlink:to="us-gaap_LesseeOperatingLeasesTextBlock_637508060359060274" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCollaborationAndLicensingAgreements" xlink:type="extended" xlink:title="11201 - Disclosure - Collaboration and Licensing Agreements">
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsAbstract" xlink:label="ardx_CollaborationAndLicensingAgreementsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CollaborativeArrangementDisclosureTextBlock" xlink:label="us-gaap_CollaborativeArrangementDisclosureTextBlock_637508060359060274" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CollaborationAndLicensingAgreementsAbstract" xlink:to="us-gaap_CollaborativeArrangementDisclosureTextBlock_637508060359060274" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureIncomeTaxes" xlink:type="extended" xlink:title="11301 - Disclosure - Income Taxes">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="IncomeTaxDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxDisclosureTextBlock" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_637508060359070290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="us-gaap_IncomeTaxDisclosureTextBlock_637508060359070290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureGeographicInformationAndConcentrations" xlink:type="extended" xlink:title="11401 - Disclosure - Geographic Information and Concentrations">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentsGeographicalAreasAbstract" xlink:label="us-gaap_SegmentsGeographicalAreasAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_GeographicInformationAndConcentrationsTextBlock" xlink:label="ardx_GeographicInformationAndConcentrationsTextBlock_637508060359070290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SegmentsGeographicalAreasAbstract" xlink:to="ardx_GeographicInformationAndConcentrationsTextBlock_637508060359070290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureNetLossPerShare" xlink:type="extended" xlink:title="11501 - Disclosure - Net Loss Per Share">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="EarningsPerShareAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareTextBlock" xlink:label="us-gaap_EarningsPerShareTextBlock_637508060359070290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="EarningsPerShareAbstract" xlink:to="us-gaap_EarningsPerShareTextBlock_637508060359070290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCommitmentsAndContingencies" xlink:type="extended" xlink:title="11601 - Disclosure - Commitments and Contingencies">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="CommitmentsAndContingenciesDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_637508060359070290" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CommitmentsAndContingenciesDisclosureAbstract" xlink:to="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_637508060359070290" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="9" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureSelectedQuarterlyFinancialDataUnaudited" xlink:type="extended" xlink:title="11701 - Disclosure - Selected Quarterly Financial Data (Unaudited)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_QuarterlyFinancialInformationDisclosureAbstract" xlink:label="QuarterlyFinancialInformationDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_QuarterlyFinancialInformationTextBlock" xlink:label="us-gaap_QuarterlyFinancialInformationTextBlock_637508060359080284" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="QuarterlyFinancialInformationDisclosureAbstract" xlink:to="us-gaap_QuarterlyFinancialInformationTextBlock_637508060359080284" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies" xlink:type="extended" xlink:title="20202 - Disclosure - Summary of Significant Accounting Policies (Policies)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="AccountingPoliciesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BasisOfAccountingPolicyPolicyTextBlock" xlink:label="us-gaap_BasisOfAccountingPolicyPolicyTextBlock_637508060359080284" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_BasisOfAccountingPolicyPolicyTextBlock_637508060359080284" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PriorPeriodErrorsPolicyTextBlock" xlink:label="ardx_PriorPeriodErrorsPolicyTextBlock_637508060359080284" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="ardx_PriorPeriodErrorsPolicyTextBlock_637508060359080284" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UseOfEstimates" xlink:label="us-gaap_UseOfEstimates_637508060359080284" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_UseOfEstimates_637508060359080284" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_LiquidityPolicyTextBlock" xlink:label="ardx_LiquidityPolicyTextBlock_637508060359080284" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="ardx_LiquidityPolicyTextBlock_637508060359080284" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock_637508060359080284" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_CashAndCashEquivalentsPolicyTextBlock_637508060359080284" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShortTermInvestmentsPolicyTextBlock" xlink:label="ardx_ShortTermInvestmentsPolicyTextBlock_637508060359130292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="ardx_ShortTermInvestmentsPolicyTextBlock_637508060359130292" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskCreditRisk" xlink:label="us-gaap_ConcentrationRiskCreditRisk_637508060359130292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_ConcentrationRiskCreditRisk_637508060359130292" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock" xlink:label="us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_ForeignCurrencyTransactionsAndTranslationsPolicyTextBlock_637508060359140301" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_637508060359140301" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock" xlink:label="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_ImpairmentOrDisposalOfLongLivedAssetsPolicyTextBlock_637508060359140301" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxPolicyTextBlock" xlink:label="us-gaap_IncomeTaxPolicyTextBlock_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_IncomeTaxPolicyTextBlock_637508060359140301" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerPolicyTextBlock" xlink:label="us-gaap_RevenueFromContractWithCustomerPolicyTextBlock_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_RevenueFromContractWithCustomerPolicyTextBlock_637508060359140301" order="12" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ResearchAndDevelopmentExpensePolicy" xlink:label="us-gaap_ResearchAndDevelopmentExpensePolicy_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_ResearchAndDevelopmentExpensePolicy_637508060359140301" order="13" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AccruedResearchAndDevelopmentExpensesPolicyPolicyTextBlock" xlink:label="ardx_AccruedResearchAndDevelopmentExpensesPolicyPolicyTextBlock_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="ardx_AccruedResearchAndDevelopmentExpensesPolicyPolicyTextBlock_637508060359140301" order="14" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CompensationRelatedCostsPolicyTextBlock" xlink:label="us-gaap_CompensationRelatedCostsPolicyTextBlock_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_CompensationRelatedCostsPolicyTextBlock_637508060359140301" order="15" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativesReportingOfDerivativeActivity" xlink:label="us-gaap_DerivativesReportingOfDerivativeActivity_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_DerivativesReportingOfDerivativeActivity_637508060359140301" order="16" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeLeasesPolicyTextBlock" xlink:label="us-gaap_LesseeLeasesPolicyTextBlock_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_LesseeLeasesPolicyTextBlock_637508060359140301" order="17" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ComprehensiveIncomePolicyPolicyTextBlock" xlink:label="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock_637508060359140301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock_637508060359140301" order="18" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerSharePolicyTextBlock" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock_637508060359150301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_EarningsPerSharePolicyTextBlock_637508060359150301" order="19" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_637508060359150301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_637508060359150301" order="20" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCashAndInvestmentsTables" xlink:type="extended" xlink:title="30303 - Disclosure - Cash and Investments (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract" xlink:label="CashAndCashEquivalentsAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ScheduleOfCashCashEquivalentsAndInvestmentsTableTextBlock" xlink:label="ardx_ScheduleOfCashCashEquivalentsAndInvestmentsTableTextBlock_637508060359150301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CashAndCashEquivalentsAbstract" xlink:to="ardx_ScheduleOfCashCashEquivalentsAndInvestmentsTableTextBlock_637508060359150301" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock_637508060359150301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CashAndCashEquivalentsAbstract" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock_637508060359150301" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureFairValueMeasurementsTables" xlink:type="extended" xlink:title="30403 - Disclosure - Fair Value Measurements (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueDisclosuresAbstract" xlink:label="FairValueDisclosuresAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock" xlink:label="us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_637508060359150301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="FairValueDisclosuresAbstract" xlink:to="us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_637508060359150301" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureDerivativeLiabilityTables" xlink:type="extended" xlink:title="30503 - Disclosure - Derivative Liability (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ScheduleOfChangesInFairValueTableTextBlock" xlink:label="ardx_ScheduleOfChangesInFairValueTableTextBlock_637508060359160300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:to="ardx_ScheduleOfChangesInFairValueTableTextBlock_637508060359160300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureBorrowingsTables" xlink:type="extended" xlink:title="30603 - Disclosure - Borrowings (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtDisclosureAbstract" xlink:label="us-gaap_DebtDisclosureAbstract_636737256074075222" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:label="us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_637508060359160300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtDisclosureAbstract_636737256074075222" xlink:to="us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_637508060359160300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansTables" xlink:type="extended" xlink:title="30803 - Disclosure - Equity Incentive Plans (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementTable" xlink:label="us-gaap_StatementTable_637508060359160300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_StatementTable_637508060359160300" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis_637508060359160300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable_637508060359160300" xlink:to="us-gaap_PlanNameAxis_637508060359160300" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain_637508060359160300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis_637508060359160300" xlink:to="us-gaap_PlanNameDomain_637508060359160300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TwoThousandFourteenEmployeeStockPurchasePlanMember" xlink:label="ardx_TwoThousandFourteenEmployeeStockPurchasePlanMember_637508060359160300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameDomain_637508060359160300" xlink:to="ardx_TwoThousandFourteenEmployeeStockPurchasePlanMember_637508060359160300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementLineItems" xlink:label="us-gaap_StatementLineItems_637508060359160300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementTable_637508060359160300" xlink:to="us-gaap_StatementLineItems_637508060359160300" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock_637508060359160300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060359160300" xlink:to="us-gaap_ScheduleOfShareBasedCompensationActivityTableTextBlock_637508060359160300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_637508060359160300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060359160300" xlink:to="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_637508060359160300" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock_637508060359170286" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060359160300" xlink:to="us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock_637508060359170286" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_637508060359170286" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060359160300" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_637508060359170286" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedPaymentArrangementExpensesNotYetRecognizedAmountTableTextBlock" xlink:label="ardx_ShareBasedPaymentArrangementExpensesNotYetRecognizedAmountTableTextBlock_637508060359170286" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementLineItems_637508060359160300" xlink:to="ardx_ShareBasedPaymentArrangementExpensesNotYetRecognizedAmountTableTextBlock_637508060359170286" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosurePropertyAndEquipmentTables" xlink:type="extended" xlink:title="30903 - Disclosure - Property and Equipment (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="PropertyPlantAndEquipmentAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_637508060359170286" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PropertyPlantAndEquipmentAbstract" xlink:to="us-gaap_PropertyPlantAndEquipmentTextBlock_637508060359170286" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesTables" xlink:type="extended" xlink:title="31003 - Disclosure - Accrued Expenses and Other Current Liabilities (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PayablesAndAccrualsAbstract" xlink:label="PayablesAndAccrualsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock" xlink:label="us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock_637508060359170286" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="us-gaap_ScheduleOfAccountsPayableAndAccruedLiabilitiesTableTextBlock_637508060359170286" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureLeasesTables" xlink:type="extended" xlink:title="31103 - Disclosure - Leases (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="us-gaap_LeasesAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ScheduleOfAdditionalDetailsOfLeasesTableTextBlock" xlink:label="ardx_ScheduleOfAdditionalDetailsOfLeasesTableTextBlock_637508060359180298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeasesAbstract" xlink:to="ardx_ScheduleOfAdditionalDetailsOfLeasesTableTextBlock_637508060359180298" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseCostTableTextBlock" xlink:label="us-gaap_LeaseCostTableTextBlock_637508060359180298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeasesAbstract" xlink:to="us-gaap_LeaseCostTableTextBlock_637508060359180298" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_637508060359180298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeasesAbstract" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_637508060359180298" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCollaborationAndLicensingAgreementsTables" xlink:type="extended" xlink:title="31203 - Disclosure - Collaboration and Licensing Agreements (Tables)">
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsAbstract" xlink:label="ardx_CollaborationAndLicensingAgreementsAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CostOfRevenueTableTextBlock" xlink:label="ardx_CostOfRevenueTableTextBlock_637508060359180298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CollaborationAndLicensingAgreementsAbstract" xlink:to="ardx_CostOfRevenueTableTextBlock_637508060359180298" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureIncomeTaxesTables" xlink:type="extended" xlink:title="31303 - Disclosure - Income Taxes (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="IncomeTaxDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_637508060359180298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_637508060359180298" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock" xlink:label="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock_637508060359180298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock_637508060359180298" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock" xlink:label="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_637508060359180298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_637508060359180298" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock" xlink:label="us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock_637508060359190304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="us-gaap_ScheduleOfUnrecognizedTaxBenefitsRollForwardTableTextBlock_637508060359190304" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureGeographicInformationAndConcentrationsTables" xlink:type="extended" xlink:title="31403 - Disclosure - Geographic Information and Concentrations (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentsGeographicalAreasAbstract" xlink:label="us-gaap_SegmentsGeographicalAreasAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock" xlink:label="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock_637508060359190304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SegmentsGeographicalAreasAbstract" xlink:to="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsByGeographicalAreasTableTextBlock_637508060359190304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SchedulesOfConcentrationOfRiskByRiskFactorTextBlock" xlink:label="us-gaap_SchedulesOfConcentrationOfRiskByRiskFactorTextBlock_637508060359190304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SegmentsGeographicalAreasAbstract" xlink:to="us-gaap_SchedulesOfConcentrationOfRiskByRiskFactorTextBlock_637508060359190304" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureNetLossPerShareTables" xlink:type="extended" xlink:title="31503 - Disclosure - Net Loss Per Share (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="EarningsPerShareAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_637508060359190304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="EarningsPerShareAbstract" xlink:to="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_637508060359190304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock" xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_637508060359190304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="EarningsPerShareAbstract" xlink:to="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_637508060359190304" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCommitmentsAndContingenciesTables" xlink:type="extended" xlink:title="31603 - Disclosure - Commitments and Contingencies (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="CommitmentsAndContingenciesDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_637508060359190304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CommitmentsAndContingenciesDisclosureAbstract" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_637508060359190304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureSelectedQuarterlyFinancialDataUnauditedTables" xlink:type="extended" xlink:title="31703 - Disclosure - Selected Quarterly Financial Data (Unaudited) (Tables)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_QuarterlyFinancialInformationDisclosureAbstract" xlink:label="QuarterlyFinancialInformationDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock" xlink:label="us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock_637508060359200298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="QuarterlyFinancialInformationDisclosureAbstract" xlink:to="us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock_637508060359200298" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureOrganizationAndBasisOfPresentationAdditionalInformationDetails" xlink:type="extended" xlink:title="40101 - Disclosure - Organization and Basis of Presentation - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:label="OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfOperatingSegments" xlink:label="us-gaap_NumberOfOperatingSegments_637508060359200298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="us-gaap_NumberOfOperatingSegments_637508060359200298" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesPriorPeriodErrorsDetails" xlink:type="extended" xlink:title="40201 - Disclosure - Summary of Significant Accounting Policies - Prior Period Errors (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="us-gaap_AccountingPoliciesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable" xlink:label="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_637508060359200298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_637508060359200298" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis" xlink:label="us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis_637508060359200298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_637508060359200298" xlink:to="us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis_637508060359200298" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsForErrorCorrectionDomain" xlink:label="us-gaap_AdjustmentsForErrorCorrectionDomain_637508060359200298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis_637508060359200298" xlink:to="us-gaap_AdjustmentsForErrorCorrectionDomain_637508060359200298" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_OverstatementDueToClinicalTrialAccrualsErrorsMember" xlink:label="ardx_OverstatementDueToClinicalTrialAccrualsErrorsMember_637508060359200298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsForErrorCorrectionDomain_637508060359200298" xlink:to="ardx_OverstatementDueToClinicalTrialAccrualsErrorsMember_637508060359200298" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RestatementAxis" xlink:label="srt_RestatementAxis_637508060359200298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_637508060359200298" xlink:to="srt_RestatementAxis_637508060359200298" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RestatementDomain" xlink:label="srt_RestatementDomain_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RestatementAxis_637508060359200298" xlink:to="srt_RestatementDomain_637508060359210304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RestatementAdjustmentMember" xlink:label="srt_RestatementAdjustmentMember_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RestatementDomain_637508060359210304" xlink:to="srt_RestatementAdjustmentMember_637508060359210304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems" xlink:label="us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_637508060359200298" xlink:to="us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems_637508060359210304" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="us-gaap_ResearchAndDevelopmentExpense_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems_637508060359210304" xlink:to="us-gaap_ResearchAndDevelopmentExpense_637508060359210304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilities" xlink:label="us-gaap_AccruedLiabilitiesAndOtherLiabilities_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems_637508060359210304" xlink:to="us-gaap_AccruedLiabilitiesAndOtherLiabilities_637508060359210304" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesCumulativeAdjustmentsDetails" xlink:type="extended" xlink:title="40202 - Disclosure - Summary of Significant Accounting Policies - Cumulative Adjustments (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="us-gaap_AccountingPoliciesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfQuantifyingPriorYearMisstatementCorrectedInCurrentYearFinancialStatementsTable" xlink:label="us-gaap_ScheduleOfQuantifyingPriorYearMisstatementCorrectedInCurrentYearFinancialStatementsTable_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_ScheduleOfQuantifyingPriorYearMisstatementCorrectedInCurrentYearFinancialStatementsTable_637508060359210304" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsByNatureOfErrorAxis" xlink:label="us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsByNatureOfErrorAxis_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfQuantifyingPriorYearMisstatementCorrectedInCurrentYearFinancialStatementsTable_637508060359210304" xlink:to="us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsByNatureOfErrorAxis_637508060359210304" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NatureOfErrorDomain" xlink:label="us-gaap_NatureOfErrorDomain_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsByNatureOfErrorAxis_637508060359210304" xlink:to="us-gaap_NatureOfErrorDomain_637508060359210304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ReductionInAccruedAndOtherLiabilitiesMember" xlink:label="ardx_ReductionInAccruedAndOtherLiabilitiesMember_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NatureOfErrorDomain_637508060359210304" xlink:to="ardx_ReductionInAccruedAndOtherLiabilitiesMember_637508060359210304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ReductionInResearchAndDevelopmentExpensesMember" xlink:label="ardx_ReductionInResearchAndDevelopmentExpensesMember_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NatureOfErrorDomain_637508060359210304" xlink:to="ardx_ReductionInResearchAndDevelopmentExpensesMember_637508060359210304" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsLineItems" xlink:label="us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsLineItems_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfQuantifyingPriorYearMisstatementCorrectedInCurrentYearFinancialStatementsTable_637508060359210304" xlink:to="us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsLineItems_637508060359210304" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsAmount" xlink:label="us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsAmount_637508060359210304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsLineItems_637508060359210304" xlink:to="us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsAmount_637508060359210304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesLiquidityDetails" xlink:type="extended" xlink:title="40203 - Disclosure - Summary of Significant Accounting Policies - Liquidity (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="us-gaap_AccountingPoliciesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable" xlink:label="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AccountingPoliciesAbstract" xlink:to="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359220287" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359220287" xlink:to="us-gaap_SubsidiarySaleOfStockAxis_637508060359220287" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis_637508060359220287" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359220287" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AtMarketOfferingMember" xlink:label="ardx_AtMarketOfferingMember_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359220287" xlink:to="ardx_AtMarketOfferingMember_637508060359220287" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CommonStockIssuance2019OfferingMember" xlink:label="ardx_CommonStockIssuance2019OfferingMember_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359220287" xlink:to="ardx_CommonStockIssuance2019OfferingMember_637508060359220287" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PrivatePlacementMember" xlink:label="us-gaap_PrivatePlacementMember_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359220287" xlink:to="us-gaap_PrivatePlacementMember_637508060359220287" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiarySaleOfStockLineItems" xlink:label="us-gaap_SubsidiarySaleOfStockLineItems_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359220287" xlink:to="us-gaap_SubsidiarySaleOfStockLineItems_637508060359220287" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InvestmentsAndCash" xlink:label="us-gaap_InvestmentsAndCash_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359220287" xlink:to="us-gaap_InvestmentsAndCash_637508060359220287" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359220287" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock_637508060359220287" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfPrivatePlacement" xlink:label="us-gaap_ProceedsFromIssuanceOfPrivatePlacement_637508060359220287" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359220287" xlink:to="us-gaap_ProceedsFromIssuanceOfPrivatePlacement_637508060359220287" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetails" xlink:type="extended" xlink:title="40204 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="AccountingPoliciesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="AccountingPoliciesAbstract" xlink:to="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_637508060359230300" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_637508060359230300" xlink:to="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_637508060359230300" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="us-gaap_TypeOfAdoptionMember_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_637508060359230300" xlink:to="us-gaap_TypeOfAdoptionMember_637508060359230300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingStandardsUpdate201409Member" xlink:label="us-gaap_AccountingStandardsUpdate201409Member_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TypeOfAdoptionMember_637508060359230300" xlink:to="us-gaap_AccountingStandardsUpdate201409Member_637508060359230300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis" xlink:label="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_637508060359230300" xlink:to="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_637508060359230300" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain" xlink:label="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_637508060359230300" xlink:to="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_637508060359230300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member" xlink:label="us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_637508060359230300" xlink:to="us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_637508060359230300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_CounterpartyNameAxis" xlink:label="srt_CounterpartyNameAxis_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_637508060359230300" xlink:to="srt_CounterpartyNameAxis_637508060359230300" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain" xlink:label="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CounterpartyNameAxis_637508060359230300" xlink:to="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359230300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_KyowaHakkoKirinMember" xlink:label="ardx_KyowaHakkoKirinMember_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359230300" xlink:to="ardx_KyowaHakkoKirinMember_637508060359230300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AstrazenecaMember" xlink:label="ardx_AstrazenecaMember_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359230300" xlink:to="ardx_AstrazenecaMember_637508060359230300" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_637508060359230300" xlink:to="srt_RangeAxis_637508060359230300" order="4" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="srt_RangeMember_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis_637508060359230300" xlink:to="srt_RangeMember_637508060359230300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="srt_MinimumMember_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeMember_637508060359230300" xlink:to="srt_MinimumMember_637508060359230300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember_637508060359230300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeMember_637508060359230300" xlink:to="srt_MaximumMember_637508060359230300" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems" xlink:label="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_637508060359240299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_637508060359230300" xlink:to="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_637508060359240299" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashAndCashEquivalentsOriginalMaturityDates" xlink:label="ardx_CashAndCashEquivalentsOriginalMaturityDates_637508060359240299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_637508060359240299" xlink:to="ardx_CashAndCashEquivalentsOriginalMaturityDates_637508060359240299" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShortTermInvestmentsMaturityPeriodDescription" xlink:label="ardx_ShortTermInvestmentsMaturityPeriodDescription_637508060359240299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_637508060359240299" xlink:to="ardx_ShortTermInvestmentsMaturityPeriodDescription_637508060359240299" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_637508060359240299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_637508060359240299" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife_637508060359240299" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ImpairmentOfLongLivedAssetsHeldForUse" xlink:label="us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_637508060359240299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_637508060359240299" xlink:to="us-gaap_ImpairmentOfLongLivedAssetsHeldForUse_637508060359240299" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_637508060359240299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_637508060359240299" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit_637508060359240299" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerAssetNetCurrent" xlink:label="us-gaap_ContractWithCustomerAssetNetCurrent_637508060359240299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_637508060359240299" xlink:to="us-gaap_ContractWithCustomerAssetNetCurrent_637508060359240299" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_UnchargedLicenseFeeCurrent" xlink:label="ardx_UnchargedLicenseFeeCurrent_637508060359240299" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_637508060359240299" xlink:to="ardx_UnchargedLicenseFeeCurrent_637508060359240299" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCashAndInvestmentsScheduleOfSecuritiesClassifiedAsCashAndInvestmentsDetails" xlink:type="extended" xlink:title="40301 - Disclosure - Cash and Investments - Schedule of Securities Classified as Cash and Investments (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract" xlink:label="CashAndCashEquivalentsAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndShortTermInvestmentsTable" xlink:label="ardx_CashCashEquivalentsAndShortTermInvestmentsTable_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CashAndCashEquivalentsAbstract" xlink:to="ardx_CashCashEquivalentsAndShortTermInvestmentsTable_637508060359250288" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="us-gaap_FinancialInstrumentAxis_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsTable_637508060359250288" xlink:to="us-gaap_FinancialInstrumentAxis_637508060359250288" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FinancialInstrumentAxis_637508060359250288" xlink:to="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_637508060359250288" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember" xlink:label="us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_637508060359250288" xlink:to="us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_637508060359250288" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:label="us-gaap_CorporateDebtSecuritiesMember_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_637508060359250288" xlink:to="us-gaap_CorporateDebtSecuritiesMember_637508060359250288" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember" xlink:label="us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_637508060359250288" xlink:to="us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_637508060359250288" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetBackedSecuritiesMember" xlink:label="us-gaap_AssetBackedSecuritiesMember_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_637508060359250288" xlink:to="us-gaap_AssetBackedSecuritiesMember_637508060359250288" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_USTreasuryNotesSecuritiesMember" xlink:label="us-gaap_USTreasuryNotesSecuritiesMember_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_637508060359250288" xlink:to="us-gaap_USTreasuryNotesSecuritiesMember_637508060359250288" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAxis" xlink:label="us-gaap_CashAndCashEquivalentsAxis_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsTable_637508060359250288" xlink:to="us-gaap_CashAndCashEquivalentsAxis_637508060359250288" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CashAndCashEquivalentsAxis_637508060359250288" xlink:to="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_637508060359250288" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MoneyMarketFundsMember" xlink:label="us-gaap_MoneyMarketFundsMember_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_637508060359250288" xlink:to="us-gaap_MoneyMarketFundsMember_637508060359250288" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommercialPaperMember" xlink:label="us-gaap_CommercialPaperMember_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_637508060359250288" xlink:to="us-gaap_CommercialPaperMember_637508060359250288" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember" xlink:label="us-gaap_CorporateDebtSecuritiesMember_6375080603592502881" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_637508060359250288" xlink:to="us-gaap_CorporateDebtSecuritiesMember_6375080603592502881" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashMember" xlink:label="us-gaap_CashMember_637508060359250288" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_637508060359250288" xlink:to="us-gaap_CashMember_637508060359250288" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems" xlink:label="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsTable_637508060359250288" xlink:to="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_637508060359260301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_637508060359260301" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherCashEquivalentsAtCarryingValue" xlink:label="us-gaap_OtherCashEquivalentsAtCarryingValue_637508060359260301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="us-gaap_OtherCashEquivalentsAtCarryingValue_637508060359260301" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="8" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashAndCashEquivalentsGrossUnrealizedGains" xlink:label="ardx_CashAndCashEquivalentsGrossUnrealizedGains_637508060359260301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_CashAndCashEquivalentsGrossUnrealizedGains_637508060359260301" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="us-gaap_CashAndCashEquivalentsFairValueDisclosure_637508060359260301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="us-gaap_CashAndCashEquivalentsFairValueDisclosure_637508060359260301" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_637508060359260301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_637508060359260301" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_637508060359260301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_637508060359260301" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_637508060359260301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_637508060359260301" order="7" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_637508060359260301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtSecurities_637508060359260301" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_LongTermInvestmentsAmortizedCost" xlink:label="ardx_LongTermInvestmentsAmortizedCost_637508060359270303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_LongTermInvestmentsAmortizedCost_637508060359270303" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_LongTermInvestmentsGrossUnrealizedLosses" xlink:label="ardx_LongTermInvestmentsGrossUnrealizedLosses_637508060359270303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_LongTermInvestmentsGrossUnrealizedLosses_637508060359270303" order="10" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_LongTermInvestmentsFairValue" xlink:label="ardx_LongTermInvestmentsFairValue_637508060359270303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_LongTermInvestmentsFairValue_637508060359270303" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/label" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashCashEquivalentsAndShortTermInvestments" xlink:label="us-gaap_CashCashEquivalentsAndShortTermInvestments_637508060359270303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="us-gaap_CashCashEquivalentsAndShortTermInvestments_637508060359270303" order="12" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InvestmentsAndCash" xlink:label="us-gaap_InvestmentsAndCash_637508060359270303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="us-gaap_InvestmentsAndCash_637508060359270303" order="13" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="8" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndShortTermInvestmentsGrossUnrealizedGains" xlink:label="ardx_CashCashEquivalentsAndShortTermInvestmentsGrossUnrealizedGains_637508060359270303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_CashCashEquivalentsAndShortTermInvestmentsGrossUnrealizedGains_637508060359270303" order="14" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndShortTermInvestmentsGrossUnrealizedLosses" xlink:label="ardx_CashCashEquivalentsAndShortTermInvestmentsGrossUnrealizedLosses_637508060359270303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_CashCashEquivalentsAndShortTermInvestmentsGrossUnrealizedLosses_637508060359270303" order="15" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndShortTermInvestmentsFairValueDisclosure" xlink:label="ardx_CashCashEquivalentsAndShortTermInvestmentsFairValueDisclosure_637508060359270303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_CashCashEquivalentsAndShortTermInvestmentsFairValueDisclosure_637508060359270303" order="16" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndInvestmentsGrossUnrealizedGains" xlink:label="ardx_CashCashEquivalentsAndInvestmentsGrossUnrealizedGains_637508060359280302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_CashCashEquivalentsAndInvestmentsGrossUnrealizedGains_637508060359280302" order="17" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndInvestmentsGrossUnrealizedLosses" xlink:label="ardx_CashCashEquivalentsAndInvestmentsGrossUnrealizedLosses_637508060359280302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_CashCashEquivalentsAndInvestmentsGrossUnrealizedLosses_637508060359280302" order="18" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndInvestmentsFairValueDisclosure" xlink:label="ardx_CashCashEquivalentsAndInvestmentsFairValueDisclosure_637508060359280302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359260301" xlink:to="ardx_CashCashEquivalentsAndInvestmentsFairValueDisclosure_637508060359280302" order="19" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCashAndInvestmentsAdditionalInformationDetails" xlink:type="extended" xlink:title="40302 - Disclosure - Cash and Investments - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract" xlink:label="CashAndCashEquivalentsAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndShortTermInvestmentsTable" xlink:label="ardx_CashCashEquivalentsAndShortTermInvestmentsTable_637508060359291144" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="CashAndCashEquivalentsAbstract" xlink:to="ardx_CashCashEquivalentsAndShortTermInvestmentsTable_637508060359291144" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis_637508060359291144" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsTable_637508060359291144" xlink:to="srt_RangeAxis_637508060359291144" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="srt_RangeMember_637508060359291144" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis_637508060359291144" xlink:to="srt_RangeMember_637508060359291144" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember_637508060359291144" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeMember_637508060359291144" xlink:to="srt_MaximumMember_637508060359291144" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems" xlink:label="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359291144" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsTable_637508060359291144" xlink:to="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359291144" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_637508060359291144" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359291144" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_637508060359291144" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AvailableForSaleSecuritiesContractualMaturityPeriod" xlink:label="ardx_AvailableForSaleSecuritiesContractualMaturityPeriod_637508060359291144" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CashCashEquivalentsAndShortTermInvestmentsLineItems_637508060359291144" xlink:to="ardx_AvailableForSaleSecuritiesContractualMaturityPeriod_637508060359291144" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCashAndInvestmentsAmortizedCostAndEstimatedFairValueOfAvailableForSaleDebtSecuritiesDetails" xlink:type="extended" xlink:title="40303 - Disclosure - Cash and Investments - Amortized Cost and Estimated Fair Value of Available-for-sale Debt Securities (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract" xlink:label="us-gaap_CashAndCashEquivalentsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CashAndCashEquivalentsAbstract" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_637508060359300294" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_637508060359300294" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_637508060359300294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DebtSecuritiesAvailableForSaleAmortizedCostMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughTwo" xlink:label="ardx_DebtSecuritiesAvailableForSaleAmortizedCostMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughTwo_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_637508060359300294" xlink:to="ardx_DebtSecuritiesAvailableForSaleAmortizedCostMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughTwo_637508060359300294" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_637508060359300294" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDateAmortizedCostBasis_637508060359300294" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CashAndCashEquivalentsAbstract" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_637508060359300294" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_637508060359300294" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_637508060359300294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DebtSecuritiesAvailableForSaleFairValueMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughFive" xlink:label="ardx_DebtSecuritiesAvailableForSaleFairValueMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughFive_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_637508060359300294" xlink:to="ardx_DebtSecuritiesAvailableForSaleFairValueMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughFive_637508060359300294" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_637508060359300294" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesSingleMaturityDate_637508060359300294" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureFairValueMeasurementsSummaryOfFairValueMeasurementsOfCompanySFinancialAssetsAndLiabilitiesDetails" xlink:type="extended" xlink:title="40401 - Disclosure - Fair Value Measurements - Summary of Fair Value Measurements of Company's Financial Assets and Liabilities (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueDisclosuresAbstract" xlink:label="FairValueDisclosuresAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="FairValueDisclosuresAbstract" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_637508060359300294" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByAssetClassAxis" xlink:label="us-gaap_FairValueByAssetClassAxis_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_637508060359300294" xlink:to="us-gaap_FairValueByAssetClassAxis_637508060359300294" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByAssetClassAxis_637508060359300294" xlink:to="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_637508060359300294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MoneyMarketFundsMember" xlink:label="us-gaap_MoneyMarketFundsMember_637508060359300294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_637508060359300294" xlink:to="us-gaap_MoneyMarketFundsMember_637508060359300294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CommercialPaperCashEquivalentsIncludingSecuritiesMember" xlink:label="ardx_CommercialPaperCashEquivalentsIncludingSecuritiesMember_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_637508060359300294" xlink:to="ardx_CommercialPaperCashEquivalentsIncludingSecuritiesMember_637508060359310302" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DomesticCorporateDebtSecuritiesIncludingCashEquivalentsMember" xlink:label="ardx_DomesticCorporateDebtSecuritiesIncludingCashEquivalentsMember_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_637508060359300294" xlink:to="ardx_DomesticCorporateDebtSecuritiesIncludingCashEquivalentsMember_637508060359310302" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember" xlink:label="us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_637508060359300294" xlink:to="us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_637508060359310302" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetBackedSecuritiesMember" xlink:label="us-gaap_AssetBackedSecuritiesMember_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_637508060359300294" xlink:to="us-gaap_AssetBackedSecuritiesMember_637508060359310302" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_USTreasuryNotesSecuritiesMember" xlink:label="us-gaap_USTreasuryNotesSecuritiesMember_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_637508060359300294" xlink:to="us-gaap_USTreasuryNotesSecuritiesMember_637508060359310302" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis" xlink:label="us-gaap_FairValueByLiabilityClassAxis_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_637508060359300294" xlink:to="us-gaap_FairValueByLiabilityClassAxis_637508060359310302" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByLiabilityClassAxis_637508060359310302" xlink:to="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_637508060359310302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DerivativeLiabilityExitFeeMember" xlink:label="ardx_DerivativeLiabilityExitFeeMember_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_637508060359310302" xlink:to="ardx_DerivativeLiabilityExitFeeMember_637508060359310302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_637508060359300294" xlink:to="us-gaap_FairValueByMeasurementFrequencyAxis_637508060359310302" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByMeasurementFrequencyAxis_637508060359310302" xlink:to="us-gaap_FairValueMeasurementFrequencyDomain_637508060359310302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueMeasurementFrequencyDomain_637508060359310302" xlink:to="us-gaap_FairValueMeasurementsRecurringMember_637508060359310302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_637508060359300294" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis_637508060359310302" order="4" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_637508060359310302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis_637508060359310302" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_637508060359310302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="us-gaap_FairValueInputsLevel1Member_637508060359320301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_637508060359310302" xlink:to="us-gaap_FairValueInputsLevel1Member_637508060359320301" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="us-gaap_FairValueInputsLevel2Member_637508060359320301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_637508060359310302" xlink:to="us-gaap_FairValueInputsLevel2Member_637508060359320301" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="us-gaap_FairValueInputsLevel3Member_637508060359320301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_637508060359310302" xlink:to="us-gaap_FairValueInputsLevel3Member_637508060359320301" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_637508060359320301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_637508060359300294" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_637508060359320301" order="5" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="us-gaap_AssetsFairValueDisclosureAbstract_637508060359320301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_637508060359320301" xlink:to="us-gaap_AssetsFairValueDisclosureAbstract_637508060359320301" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="us-gaap_AssetsFairValueDisclosure_637508060359320301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsFairValueDisclosureAbstract_637508060359320301" xlink:to="us-gaap_AssetsFairValueDisclosure_637508060359320301" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="us-gaap_LiabilitiesFairValueDisclosureAbstract_637508060359320301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_637508060359320301" xlink:to="us-gaap_LiabilitiesFairValueDisclosureAbstract_637508060359320301" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/label" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_637508060359320301" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LiabilitiesFairValueDisclosureAbstract_637508060359320301" xlink:to="us-gaap_LiabilitiesFairValueDisclosure_637508060359320301" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureDerivativeLiabilityAdditionalInformationDetails" xlink:type="extended" xlink:title="40501 - Disclosure - Derivative Liability - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_636737256074426150" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeTable" xlink:label="us-gaap_DerivativeTable_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_636737256074426150" xlink:to="us-gaap_DerivativeTable_637508060359330294" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="us-gaap_DebtInstrumentAxis_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeTable_637508060359330294" xlink:to="us-gaap_DebtInstrumentAxis_637508060359330294" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentAxis_637508060359330294" xlink:to="us-gaap_DebtInstrumentNameDomain_637508060359330294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_SolarCapitalAndWesternAllianceBankLoanAgreementMember" xlink:label="ardx_SolarCapitalAndWesternAllianceBankLoanAgreementMember_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentNameDomain_637508060359330294" xlink:to="ardx_SolarCapitalAndWesternAllianceBankLoanAgreementMember_637508060359330294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeTable_637508060359330294" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis_637508060359330294" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis_637508060359330294" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_637508060359330294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="us-gaap_FairValueInputsLevel3Member_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_637508060359330294" xlink:to="us-gaap_FairValueInputsLevel3Member_637508060359330294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeTable_637508060359330294" xlink:to="srt_RangeAxis_637508060359330294" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="srt_RangeMember_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis_637508060359330294" xlink:to="srt_RangeMember_637508060359330294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeMember_637508060359330294" xlink:to="srt_MaximumMember_637508060359330294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="us-gaap_DerivativeLineItems_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeTable_637508060359330294" xlink:to="us-gaap_DerivativeLineItems_637508060359330294" order="4" use="optional" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessExitCosts1" xlink:label="us-gaap_BusinessExitCosts1_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeLineItems_637508060359330294" xlink:to="us-gaap_BusinessExitCosts1_637508060359330294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_FairValueInputsPotentialMilestonePaymentAsResultOfFoodAndDrugsAdministrationApproval" xlink:label="ardx_FairValueInputsPotentialMilestonePaymentAsResultOfFoodAndDrugsAdministrationApproval_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeLineItems_637508060359330294" xlink:to="ardx_FairValueInputsPotentialMilestonePaymentAsResultOfFoodAndDrugsAdministrationApproval_637508060359330294" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PercentageOfReasonablyPossibleIncreaseInRiskAssumption" xlink:label="ardx_PercentageOfReasonablyPossibleIncreaseInRiskAssumption_637508060359330294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeLineItems_637508060359330294" xlink:to="ardx_PercentageOfReasonablyPossibleIncreaseInRiskAssumption_637508060359330294" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PercentageOfReasonablyPossibleDecreaseInRiskAssumption" xlink:label="ardx_PercentageOfReasonablyPossibleDecreaseInRiskAssumption_637508060359340300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeLineItems_637508060359330294" xlink:to="ardx_PercentageOfReasonablyPossibleDecreaseInRiskAssumption_637508060359340300" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IncreaseDecreaseInFinancialInstrumentDueToReasonablyPossibleIncreaseInDesignatedRiskComponent" xlink:label="ardx_IncreaseDecreaseInFinancialInstrumentDueToReasonablyPossibleIncreaseInDesignatedRiskComponent_637508060359340300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeLineItems_637508060359330294" xlink:to="ardx_IncreaseDecreaseInFinancialInstrumentDueToReasonablyPossibleIncreaseInDesignatedRiskComponent_637508060359340300" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IncreaseDecreaseInFinancialInstrumentDueToReasonablyPossibleDecreaseInDesignatedRiskComponent" xlink:label="ardx_IncreaseDecreaseInFinancialInstrumentDueToReasonablyPossibleDecreaseInDesignatedRiskComponent_637508060359340300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeLineItems_637508060359330294" xlink:to="ardx_IncreaseDecreaseInFinancialInstrumentDueToReasonablyPossibleDecreaseInDesignatedRiskComponent_637508060359340300" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureDerivativeLiabilityScheduleOfChangesInFairValueDetails" xlink:type="extended" xlink:title="40502 - Disclosure - Derivative Liability - Schedule of Changes in Fair Value (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="us-gaap_DerivativeFairValueOfDerivativeLiability_637508060359340300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:to="us-gaap_DerivativeFairValueOfDerivativeLiability_637508060359340300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrealizedGainLossOnDerivatives" xlink:label="us-gaap_UnrealizedGainLossOnDerivatives_637508060359340300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:to="us-gaap_UnrealizedGainLossOnDerivatives_637508060359340300" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:label="us-gaap_DerivativeFairValueOfDerivativeLiability_6375080603593403001" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract" xlink:to="us-gaap_DerivativeFairValueOfDerivativeLiability_6375080603593403001" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureBorrowingsDetails" xlink:type="extended" xlink:title="40601 - Disclosure - Borrowings (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtDisclosureAbstract" xlink:label="us-gaap_DebtDisclosureAbstract_636737256074436181" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="us-gaap_DebtInstrumentTable_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtDisclosureAbstract_636737256074436181" xlink:to="us-gaap_DebtInstrumentTable_637508060359350302" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="us-gaap_VariableRateAxis_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentTable_637508060359350302" xlink:to="us-gaap_VariableRateAxis_637508060359350302" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="us-gaap_VariableRateDomain_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_VariableRateAxis_637508060359350302" xlink:to="us-gaap_VariableRateDomain_637508060359350302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_VariableRateDomain_637508060359350302" xlink:to="us-gaap_LondonInterbankOfferedRateLIBORMember_637508060359350302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis" xlink:label="us-gaap_DebtInstrumentRedemptionPeriodAxis_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentTable_637508060359350302" xlink:to="us-gaap_DebtInstrumentRedemptionPeriodAxis_637508060359350302" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:label="us-gaap_DebtInstrumentRedemptionPeriodDomain_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentRedemptionPeriodAxis_637508060359350302" xlink:to="us-gaap_DebtInstrumentRedemptionPeriodDomain_637508060359350302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AtMaturityMember" xlink:label="ardx_AtMaturityMember_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentRedemptionPeriodDomain_637508060359350302" xlink:to="ardx_AtMaturityMember_637508060359350302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodOneMember" xlink:label="us-gaap_DebtInstrumentRedemptionPeriodOneMember_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentRedemptionPeriodDomain_637508060359350302" xlink:to="us-gaap_DebtInstrumentRedemptionPeriodOneMember_637508060359350302" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodTwoMember" xlink:label="us-gaap_DebtInstrumentRedemptionPeriodTwoMember_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentRedemptionPeriodDomain_637508060359350302" xlink:to="us-gaap_DebtInstrumentRedemptionPeriodTwoMember_637508060359350302" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AfterSecondAnniversaryToMaturityDateMember" xlink:label="ardx_AfterSecondAnniversaryToMaturityDateMember_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentRedemptionPeriodDomain_637508060359350302" xlink:to="ardx_AfterSecondAnniversaryToMaturityDateMember_637508060359350302" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="us-gaap_DebtInstrumentLineItems_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentTable_637508060359350302" xlink:to="us-gaap_DebtInstrumentLineItems_637508060359350302" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="us-gaap_DebtInstrumentFaceAmount_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="us-gaap_DebtInstrumentFaceAmount_637508060359350302" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromDebtNetOfIssuanceCosts" xlink:label="us-gaap_ProceedsFromDebtNetOfIssuanceCosts_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="us-gaap_ProceedsFromDebtNetOfIssuanceCosts_637508060359350302" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_637508060359350302" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage_637508060359350302" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis" xlink:label="us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_637508060359360303" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DebtInstrumentInterestPaymentExtensionTerm" xlink:label="ardx_DebtInstrumentInterestPaymentExtensionTerm_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="ardx_DebtInstrumentInterestPaymentExtensionTerm_637508060359360303" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_FeePayableUponClosingOfTermLoan" xlink:label="ardx_FeePayableUponClosingOfTermLoan_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="ardx_FeePayableUponClosingOfTermLoan_637508060359360303" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PrepaymentFeePercentage" xlink:label="ardx_PrepaymentFeePercentage_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="ardx_PrepaymentFeePercentage_637508060359360303" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DebtInstrumentFinalPaymentFeePercentage" xlink:label="ardx_DebtInstrumentFinalPaymentFeePercentage_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="ardx_DebtInstrumentFinalPaymentFeePercentage_637508060359360303" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DefaultInterestRate" xlink:label="ardx_DefaultInterestRate_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="ardx_DefaultInterestRate_637508060359360303" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebtByMaturityAbstract" xlink:label="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DebtInstrumentLineItems_637508060359350302" xlink:to="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" xlink:to="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_637508060359360303" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" xlink:to="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_637508060359360303" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="us-gaap_DebtInstrumentCarryingAmount_637508060359360303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" xlink:to="us-gaap_DebtInstrumentCarryingAmount_637508060359360303" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="9" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_637508060359370305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" xlink:to="us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_637508060359370305" order="4" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DebtInstrumentUnaccretedValueFinalFee" xlink:label="ardx_DebtInstrumentUnaccretedValueFinalFee_637508060359370305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" xlink:to="ardx_DebtInstrumentUnaccretedValueFinalFee_637508060359370305" order="5" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebt" xlink:label="us-gaap_LongTermDebt_637508060359370305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" xlink:to="us-gaap_LongTermDebt_637508060359370305" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LoansPayableCurrent" xlink:label="us-gaap_LoansPayableCurrent_637508060359370305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" xlink:to="us-gaap_LoansPayableCurrent_637508060359370305" order="7" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="8" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermLoansPayable" xlink:label="us-gaap_LongTermLoansPayable_637508060359370305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LongTermDebtByMaturityAbstract_637508060359360303" xlink:to="us-gaap_LongTermLoansPayable_637508060359370305" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="7" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureStockholdersEquityDetails" xlink:type="extended" xlink:title="40701 - Disclosure - Stockholders' Equity (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityNoteAbstract" xlink:label="us-gaap_StockholdersEquityNoteAbstract_636737256074516375" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable" xlink:label="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359370305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StockholdersEquityNoteAbstract_636737256074516375" xlink:to="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359370305" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="us-gaap_StatementClassOfStockAxis_637508060359370305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359370305" xlink:to="us-gaap_StatementClassOfStockAxis_637508060359370305" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="us-gaap_ClassOfStockDomain_637508060359370305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_StatementClassOfStockAxis_637508060359370305" xlink:to="us-gaap_ClassOfStockDomain_637508060359370305" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockMember" xlink:label="us-gaap_CommonStockMember_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ClassOfStockDomain_637508060359370305" xlink:to="us-gaap_CommonStockMember_637508060359380291" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359370305" xlink:to="us-gaap_SubsidiarySaleOfStockAxis_637508060359380291" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockAxis_637508060359380291" xlink:to="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359380291" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CommonStockIssuanceMay2018OfferingMember" xlink:label="ardx_CommonStockIssuanceMay2018OfferingMember_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359380291" xlink:to="ardx_CommonStockIssuanceMay2018OfferingMember_637508060359380291" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CommonStockIssuance2019OfferingMember" xlink:label="ardx_CommonStockIssuance2019OfferingMember_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359380291" xlink:to="ardx_CommonStockIssuance2019OfferingMember_637508060359380291" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AtMarketOfferingMember" xlink:label="ardx_AtMarketOfferingMember_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359380291" xlink:to="ardx_AtMarketOfferingMember_637508060359380291" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OverAllotmentOptionMember" xlink:label="us-gaap_OverAllotmentOptionMember_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359380291" xlink:to="us-gaap_OverAllotmentOptionMember_637508060359380291" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PrivatePlacementMember" xlink:label="us-gaap_PrivatePlacementMember_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359380291" xlink:to="us-gaap_PrivatePlacementMember_637508060359380291" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CommonStockIssuance2019OfferingAndOverAllotmentOptionMember" xlink:label="ardx_CommonStockIssuance2019OfferingAndOverAllotmentOptionMember_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SaleOfStockNameOfTransactionDomain_637508060359380291" xlink:to="ardx_CommonStockIssuance2019OfferingAndOverAllotmentOptionMember_637508060359380291" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359370305" xlink:to="us-gaap_SubsequentEventTypeAxis_637508060359380291" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventTypeAxis_637508060359380291" xlink:to="us-gaap_SubsequentEventTypeDomain_637508060359380291" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsequentEventTypeDomain_637508060359380291" xlink:to="us-gaap_SubsequentEventMember_637508060359380291" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SubsidiarySaleOfStockLineItems" xlink:label="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_637508060359370305" xlink:to="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" order="4" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_637508060359390304" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharesIssuedPricePerShare" xlink:label="us-gaap_SharesIssuedPricePerShare_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="us-gaap_SharesIssuedPricePerShare_637508060359390304" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_637508060359390304" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_WarrantTerm" xlink:label="ardx_WarrantTerm_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="ardx_WarrantTerm_637508060359390304" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_WarrantsExercisedInPeriod" xlink:label="ardx_WarrantsExercisedInPeriod_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="ardx_WarrantsExercisedInPeriod_637508060359390304" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues" xlink:label="us-gaap_StockIssuedDuringPeriodSharesNewIssues_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="us-gaap_StockIssuedDuringPeriodSharesNewIssues_637508060359390304" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="us-gaap_CommonStockSharesIssued_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="us-gaap_CommonStockSharesIssued_637508060359390304" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharePrice" xlink:label="us-gaap_SharePrice_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="us-gaap_SharePrice_637508060359390304" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_MaximumAggregateOfferingPrice" xlink:label="ardx_MaximumAggregateOfferingPrice_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="ardx_MaximumAggregateOfferingPrice_637508060359390304" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_WeightedAverageSharePrice" xlink:label="ardx_WeightedAverageSharePrice_637508060359390304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="ardx_WeightedAverageSharePrice_637508060359390304" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_StockIssuanceCostCommissionPercent" xlink:label="ardx_StockIssuanceCostCommissionPercent_637508060359400304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="ardx_StockIssuanceCostCommissionPercent_637508060359400304" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_UnderwritingDiscountsAndCommissions" xlink:label="ardx_UnderwritingDiscountsAndCommissions_637508060359400304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="ardx_UnderwritingDiscountsAndCommissions_637508060359400304" order="12" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_NumberOfDaysToUnderwriterToSellAdditionalCommonShares" xlink:label="ardx_NumberOfDaysToUnderwriterToSellAdditionalCommonShares_637508060359400304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="ardx_NumberOfDaysToUnderwriterToSellAdditionalCommonShares_637508060359400304" order="13" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ProceedsFromIssuanceOfCommonStockGross" xlink:label="ardx_ProceedsFromIssuanceOfCommonStockGross_637508060359400304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="ardx_ProceedsFromIssuanceOfCommonStockGross_637508060359400304" order="14" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_637508060359400304" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SubsidiarySaleOfStockLineItems_637508060359380291" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock_637508060359400304" order="15" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansAdditionalInformationDetails" xlink:type="extended" xlink:title="40801 - Disclosure - Equity Incentive Plans - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_636737256074536433" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_636737256074536433" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359410292" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359410292" xlink:to="us-gaap_AwardTypeAxis_637508060359410292" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359410292" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359410292" xlink:to="us-gaap_RestrictedStockUnitsRSUMember_637508060359410292" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PerformanceBasedRestrictedStockUnitsMember" xlink:label="ardx_PerformanceBasedRestrictedStockUnitsMember_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359410292" xlink:to="ardx_PerformanceBasedRestrictedStockUnitsMember_637508060359410292" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359410292" xlink:to="us-gaap_PlanNameAxis_637508060359410292" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis_637508060359410292" xlink:to="us-gaap_PlanNameDomain_637508060359410292" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TwoThousandFourteenEquityIncentiveAwardPlanMember" xlink:label="ardx_TwoThousandFourteenEquityIncentiveAwardPlanMember_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameDomain_637508060359410292" xlink:to="ardx_TwoThousandFourteenEquityIncentiveAwardPlanMember_637508060359410292" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TwoThousandEightStockIncentivePlanMember" xlink:label="ardx_TwoThousandEightStockIncentivePlanMember_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameDomain_637508060359410292" xlink:to="ardx_TwoThousandEightStockIncentivePlanMember_637508060359410292" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TwoThousandSixteenEmploymentCommencementIncentivePlanMember" xlink:label="ardx_TwoThousandSixteenEmploymentCommencementIncentivePlanMember_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameDomain_637508060359410292" xlink:to="ardx_TwoThousandSixteenEmploymentCommencementIncentivePlanMember_637508060359410292" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_TitleOfIndividualAxis" xlink:label="srt_TitleOfIndividualAxis_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359410292" xlink:to="srt_TitleOfIndividualAxis_637508060359410292" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="srt_TitleOfIndividualWithRelationshipToEntityDomain_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_TitleOfIndividualAxis_637508060359410292" xlink:to="srt_TitleOfIndividualWithRelationshipToEntityDomain_637508060359410292" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_BoardOfDirectorsChairmanMember" xlink:label="srt_BoardOfDirectorsChairmanMember_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_TitleOfIndividualWithRelationshipToEntityDomain_637508060359410292" xlink:to="srt_BoardOfDirectorsChairmanMember_637508060359410292" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" order="4" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_637508060359410292" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_637508060359410292" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_637508060359420305" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_637508060359420305" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_637508060359420305" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_637508060359420305" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DeferredCompensationArrangementWithIndividualIncreaseInCommonStockReservedForFutureIssuance" xlink:label="ardx_DeferredCompensationArrangementWithIndividualIncreaseInCommonStockReservedForFutureIssuance_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="ardx_DeferredCompensationArrangementWithIndividualIncreaseInCommonStockReservedForFutureIssuance_637508060359420305" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_637508060359420305" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IncreaseInSharesReservedForIssuanceMaximumSharesToBeIssuedUpOnExerciseOfStockOptions" xlink:label="ardx_IncreaseInSharesReservedForIssuanceMaximumSharesToBeIssuedUpOnExerciseOfStockOptions_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="ardx_IncreaseInSharesReservedForIssuanceMaximumSharesToBeIssuedUpOnExerciseOfStockOptions_637508060359420305" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_637508060359420305" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquitySecuritiesFvNiMeasurementInput" xlink:label="us-gaap_EquitySecuritiesFvNiMeasurementInput_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_EquitySecuritiesFvNiMeasurementInput_637508060359420305" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_637508060359420305" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_637508060359420305" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_637508060359430308" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_637508060359430308" order="12" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_637508060359430308" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_637508060359430308" order="13" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_637508060359430308" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_637508060359430308" order="14" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_637508060359430308" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense_637508060359430308" order="15" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_637508060359430308" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_637508060359430308" order="16" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_637508060359430308" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_637508060359430308" order="17" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:label="us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_637508060359430308" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_637508060359430308" order="18" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAcceleratedCompensationCost" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAcceleratedCompensationCost_637508060359440347" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAcceleratedCompensationCost_637508060359440347" order="19" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_637508060359440347" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_637508060359440347" order="20" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices" xlink:label="us-gaap_StockIssuedDuringPeriodValueIssuedForServices_637508060359440347" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359410292" xlink:to="us-gaap_StockIssuedDuringPeriodValueIssuedForServices_637508060359440347" order="21" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansSummaryOfActivityUnder2008Plan2014PlanAndInducementPlanIncludingGrantsToNonemployeesIssuedDetails" xlink:type="extended" xlink:title="40802 - Disclosure - Equity Incentive Plans - Summary of Activity Under 2008 Plan, 2014 Plan and Inducement Plan Including Grants to Nonemployees Issued (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_637508060359440347" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_637508060359440347" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsAuthorized" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsAuthorized_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsAuthorized_637508060359450317" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_637508060359450317" order="3" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsExercisedInPeriod" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsExercisedInPeriod_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsExercisedInPeriod_637508060359450317" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationForfeited" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationForfeited_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationForfeited_637508060359450317" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_StockIssuedDuringPeriodSharesIssuedOfServicesAndRestrictedStockUnitsNetOfForfeitures" xlink:label="ardx_StockIssuedDuringPeriodSharesIssuedOfServicesAndRestrictedStockUnitsNetOfForfeitures_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_StockIssuedDuringPeriodSharesIssuedOfServicesAndRestrictedStockUnitsNetOfForfeitures_637508060359450317" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices" xlink:label="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_637508060359450317" order="7" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_637508060359450317" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_637508060359450317" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAuthorizedInPeriodGross" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAuthorizedInPeriodGross_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAuthorizedInPeriodGross_637508060359450317" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_6375080603594503171" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_6375080603594503171" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_637508060359450317" order="12" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_637508060359450317" order="13" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsIssuanceOfCommonStockForServicesInPeriodGross" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsIssuanceOfCommonStockForServicesInPeriodGross_637508060359450317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsIssuanceOfCommonStockForServicesInPeriodGross_637508060359450317" order="14" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_637508060359460297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_637508060359460297" order="15" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVest" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVest_637508060359460297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVest_637508060359460297" order="16" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_637508060359460297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_637508060359460297" order="17" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_637508060359460297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_637508060359460297" order="18" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_637508060359460297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_637508060359460297" order="19" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_637508060359460297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_637508060359460297" order="20" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_637508060359460297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_637508060359460297" order="21" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIssuanceOfCommonStockForServicesInPeriodWeightedAverageExercisePrice" xlink:label="ardx_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIssuanceOfCommonStockForServicesInPeriodWeightedAverageExercisePrice_637508060359460297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsIssuanceOfCommonStockForServicesInPeriodWeightedAverageExercisePrice_637508060359460297" order="22" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_6375080603594602971" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_6375080603594602971" order="23" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestWeightedAverageExercisePrice" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestWeightedAverageExercisePrice_637508060359460297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestWeightedAverageExercisePrice_637508060359460297" order="24" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_637508060359470312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_637508060359470312" order="25" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_637508060359470312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_637508060359470312" order="26" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestWeightedAverageRemainingContractualTerm" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestWeightedAverageRemainingContractualTerm_637508060359470312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestWeightedAverageRemainingContractualTerm_637508060359470312" order="27" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_637508060359470312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_637508060359470312" order="28" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_637508060359470312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_637508060359470312" order="29" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestIntrinsicValue" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestIntrinsicValue_637508060359470312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpectedToVestIntrinsicValue_637508060359470312" order="30" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_637508060359470312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_637508060359470312" order="31" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansSummaryOfNonVestedRsuActivityDetails" xlink:type="extended" xlink:title="40803 - Disclosure - Equity Incentive Plans - Summary of Non-Vested RSU Activity (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359480311" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359480311" xlink:to="us-gaap_AwardTypeAxis_637508060359480311" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359480311" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359480311" xlink:to="us-gaap_RestrictedStockUnitsRSUMember_637508060359480311" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ServiceBasedRestrictedStockUnitsMember" xlink:label="ardx_ServiceBasedRestrictedStockUnitsMember_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RestrictedStockUnitsRSUMember_637508060359480311" xlink:to="ardx_ServiceBasedRestrictedStockUnitsMember_637508060359480311" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PerformanceBasedRestrictedStockUnitsMember" xlink:label="ardx_PerformanceBasedRestrictedStockUnitsMember_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RestrictedStockUnitsRSUMember_637508060359480311" xlink:to="ardx_PerformanceBasedRestrictedStockUnitsMember_637508060359480311" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_637508060359480311" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_637508060359480311" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_637508060359480311" order="3" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_637508060359480311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_637508060359480311" order="4" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_637508060359490297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_637508060359490297" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_637508060359490297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_637508060359490297" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_637508060359490297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_637508060359490297" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_637508060359490297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_637508060359490297" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_637508060359490297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_637508060359490297" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_6375080603594902971" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359480311" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_6375080603594902971" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansSummaryOfWeightedAverageAssumptionsToEstimateFairValueOfEmployeeStockOptionsDetails" xlink:type="extended" xlink:title="40804 - Disclosure - Equity Incentive Plans - Summary of Weighted-Average Assumptions to Estimate Fair Value of Employee Stock Options (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359490297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359490297" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis_637508060359490297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359490297" xlink:to="us-gaap_PlanNameAxis_637508060359490297" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain_637508060359490297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis_637508060359490297" xlink:to="us-gaap_PlanNameDomain_637508060359490297" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TwoThousandFourteenEmployeeStockPurchasePlanMember" xlink:label="ardx_TwoThousandFourteenEmployeeStockPurchasePlanMember_637508060359490297" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameDomain_637508060359490297" xlink:to="ardx_TwoThousandFourteenEmployeeStockPurchasePlanMember_637508060359490297" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359490297" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_637508060359500309" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_637508060359500309" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_637508060359500309" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_637508060359500309" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansEmployeeStockPurchasePlanDetails" xlink:type="extended" xlink:title="40805 - Disclosure - Equity Incentive Plans - Employee Stock Purchase Plan (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359500309" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359500309" xlink:to="us-gaap_PlanNameAxis_637508060359500309" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis_637508060359500309" xlink:to="us-gaap_PlanNameDomain_637508060359500309" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TwoThousandFourteenEmployeeStockPurchasePlanMember" xlink:label="ardx_TwoThousandFourteenEmployeeStockPurchasePlanMember_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameDomain_637508060359500309" xlink:to="ardx_TwoThousandFourteenEmployeeStockPurchasePlanMember_637508060359500309" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359500309" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_637508060359500309" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsAuthorized" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsAuthorized_637508060359500309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsAuthorized_637508060359500309" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsPurchases" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsPurchases_637508060359510298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrantOptionsPurchases_637508060359510298" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_637508060359510298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_637508060359510298" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_637508060359510298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_637508060359510298" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_637508060359510298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_637508060359510298" order="6" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_6375080603595102981" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_6375080603595102981" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasedPriceOfShare" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasedPriceOfShare_637508060359510298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasedPriceOfShare_637508060359510298" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrossProceeds" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrossProceeds_637508060359510298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrossProceeds_637508060359510298" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_637508060359510298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_637508060359510298" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_637508060359510298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_637508060359510298" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IncreaseInSharesReservedForIssuanceMaximumSharesToBeIssuedUpOnExerciseOfStockOptions" xlink:label="ardx_IncreaseInSharesReservedForIssuanceMaximumSharesToBeIssuedUpOnExerciseOfStockOptions_637508060359510298" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359500309" xlink:to="ardx_IncreaseInSharesReservedForIssuanceMaximumSharesToBeIssuedUpOnExerciseOfStockOptions_637508060359510298" order="12" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansSummaryOfStockBasedCompensationExpenseRecognizedDetails" xlink:type="extended" xlink:title="40806 - Disclosure - Equity Incentive Plans - Summary of Stock-Based Compensation Expense Recognized (Details)">
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceAndAdditionalDisclosuresAbstract" xlink:label="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceAndAdditionalDisclosuresAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceAndAdditionalDisclosuresAbstract" xlink:to="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_637508060359520312" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="us-gaap_IncomeStatementLocationAxis_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_637508060359520312" xlink:to="us-gaap_IncomeStatementLocationAxis_637508060359520312" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="us-gaap_IncomeStatementLocationDomain_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementLocationAxis_637508060359520312" xlink:to="us-gaap_IncomeStatementLocationDomain_637508060359520312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementLocationDomain_637508060359520312" xlink:to="us-gaap_ResearchAndDevelopmentExpenseMember_637508060359520312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember" xlink:label="us-gaap_GeneralAndAdministrativeExpenseMember_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeStatementLocationDomain_637508060359520312" xlink:to="us-gaap_GeneralAndAdministrativeExpenseMember_637508060359520312" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_637508060359520312" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_637508060359520312" order="2" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_637508060359520312" xlink:to="us-gaap_AllocatedShareBasedCompensationExpense_637508060359520312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureEquityIncentivePlansUnrecognizedStockBasedCompensationDetails" xlink:type="extended" xlink:title="40807 - Disclosure - Equity Incentive Plans - Unrecognized Stock-Based Compensation (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_637187467723143144" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_637187467723143144" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359520312" order="1" use="optional" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359520312" xlink:to="us-gaap_PlanNameAxis_637508060359520312" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameAxis_637508060359520312" xlink:to="us-gaap_PlanNameDomain_637508060359520312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_EmployeeStockPurchasePlanMember" xlink:label="ardx_EmployeeStockPurchasePlanMember_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PlanNameDomain_637508060359520312" xlink:to="ardx_EmployeeStockPurchasePlanMember_637508060359520312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis_637508060359520312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359520312" xlink:to="us-gaap_AwardTypeAxis_637508060359520312" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AwardTypeAxis_637508060359520312" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359530312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="us-gaap_EmployeeStockOptionMember_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359530312" xlink:to="us-gaap_EmployeeStockOptionMember_637508060359530312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_637508060359530312" xlink:to="us-gaap_RestrictedStockUnitsRSUMember_637508060359530312" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_637508060359520312" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359530312" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359530312" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_637508060359530312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_637508060359530312" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_637508060359530312" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosurePropertyAndEquipmentSummaryOfPropertyAndEquipmentDetails" xlink:type="extended" xlink:title="40901 - Disclosure - Property and Equipment - Summary of Property and Equipment (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="PropertyPlantAndEquipmentAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PropertyPlantAndEquipmentAbstract" xlink:to="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_637508060359530312" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_637508060359530312" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis_637508060359530312" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis_637508060359530312" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_637508060359530312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_LaboratoryEquipmentMember" xlink:label="ardx_LaboratoryEquipmentMember_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain_637508060359530312" xlink:to="ardx_LaboratoryEquipmentMember_637508060359530312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_OfficeEquipmentAndFurnitureMember" xlink:label="ardx_OfficeEquipmentAndFurnitureMember_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain_637508060359530312" xlink:to="ardx_OfficeEquipmentAndFurnitureMember_637508060359530312" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="us-gaap_LeaseholdImprovementsMember_637508060359530312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain_637508060359530312" xlink:to="us-gaap_LeaseholdImprovementsMember_637508060359530312" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_637508060359540312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_637508060359530312" xlink:to="us-gaap_PropertyPlantAndEquipmentLineItems_637508060359540312" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_637508060359540312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems_637508060359540312" xlink:to="us-gaap_PropertyPlantAndEquipmentGross_637508060359540312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_637508060359540312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems_637508060359540312" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_637508060359540312" order="2" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_637508060359540312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems_637508060359540312" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_637508060359540312" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosurePropertyAndEquipmentAdditionalInformationDetails" xlink:type="extended" xlink:title="40902 - Disclosure - Property and Equipment - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentAbstract" xlink:label="PropertyPlantAndEquipmentAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DepreciationAndAmortization" xlink:label="us-gaap_DepreciationAndAmortization_637508060359540312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PropertyPlantAndEquipmentAbstract" xlink:to="us-gaap_DepreciationAndAmortization_637508060359540312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureAccruedExpensesAndOtherCurrentLiabilitiesScheduleOfAccruedLiabilitiesAndOtherLiabilitiesDetails" xlink:type="extended" xlink:title="41001 - Disclosure - Accrued Expenses and Other Current Liabilities - Schedule of Accrued Liabilities and Other Liabilities (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PayablesAndAccrualsAbstract" xlink:label="PayablesAndAccrualsAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AccruedClinicalExpenses" xlink:label="ardx_AccruedClinicalExpenses_637508060359540312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="ardx_AccruedClinicalExpenses_637508060359540312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AccruedContractManufacturingCosts" xlink:label="ardx_AccruedContractManufacturingCosts_637508060359540312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="ardx_AccruedContractManufacturingCosts_637508060359540312" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DerivativeLiabilityForExitFee" xlink:label="ardx_DerivativeLiabilityForExitFee_637508060359540312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="ardx_DerivativeLiabilityForExitFee_637508060359540312" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AccruedSalesAndMarketingExpenses" xlink:label="ardx_AccruedSalesAndMarketingExpenses_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="ardx_AccruedSalesAndMarketingExpenses_637508060359550300" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AccruedProfessionalAndConsultantFeesCurrent" xlink:label="ardx_AccruedProfessionalAndConsultantFeesCurrent_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="ardx_AccruedProfessionalAndConsultantFeesCurrent_637508060359550300" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AccruedRegulatoryServices" xlink:label="ardx_AccruedRegulatoryServices_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="ardx_AccruedRegulatoryServices_637508060359550300" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/label" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:label="us-gaap_OtherLiabilitiesCurrent_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="us-gaap_OtherLiabilitiesCurrent_637508060359550300" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilities" xlink:label="us-gaap_AccruedLiabilitiesAndOtherLiabilities_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="PayablesAndAccrualsAbstract" xlink:to="us-gaap_AccruedLiabilitiesAndOtherLiabilities_637508060359550300" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureLeasesDetails" xlink:type="extended" xlink:title="41101 - Disclosure - Leases (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="us-gaap_LeasesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable" xlink:label="us-gaap_LesseeLeaseDescriptionTable_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeasesAbstract" xlink:to="us-gaap_LesseeLeaseDescriptionTable_637508060359550300" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LesseeLeaseDescriptionTable_637508060359550300" xlink:to="srt_RangeAxis_637508060359550300" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="srt_RangeMember_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis_637508060359550300" xlink:to="srt_RangeMember_637508060359550300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeMember_637508060359550300" xlink:to="srt_MaximumMember_637508060359550300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LesseeLeaseDescriptionTable_637508060359550300" xlink:to="us-gaap_LesseeLeaseDescriptionLineItems_637508060359550300" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_NumberOfOperatingLeaseArrangements" xlink:label="ardx_NumberOfOperatingLeaseArrangements_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems_637508060359550300" xlink:to="ardx_NumberOfOperatingLeaseArrangements_637508060359550300" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AreaOfRealEstateProperty" xlink:label="us-gaap_AreaOfRealEstateProperty_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems_637508060359550300" xlink:to="us-gaap_AreaOfRealEstateProperty_637508060359550300" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseExistenceOfOptionToExtend" xlink:label="us-gaap_LesseeOperatingLeaseExistenceOfOptionToExtend_637508060359550300" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems_637508060359550300" xlink:to="us-gaap_LesseeOperatingLeaseExistenceOfOptionToExtend_637508060359550300" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm" xlink:label="us-gaap_LesseeOperatingLeaseRenewalTerm_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems_637508060359550300" xlink:to="us-gaap_LesseeOperatingLeaseRenewalTerm_637508060359560312" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems_637508060359550300" xlink:to="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_637508060359560312" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems_637508060359550300" xlink:to="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_637508060359560312" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="5" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureLeasesBalanceSheetAndStatementOfOperationsDetails" xlink:type="extended" xlink:title="41102 - Disclosure - Leases - Balance Sheet and Statement of Operations (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="us-gaap_LeasesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AssetsAndLiabilitiesLesseeAbstract" xlink:label="us-gaap_AssetsAndLiabilitiesLesseeAbstract_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeasesAbstract" xlink:to="us-gaap_AssetsAndLiabilitiesLesseeAbstract_637508060359560312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAndLiabilitiesLesseeAbstract_637508060359560312" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset_637508060359560312" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAndLiabilitiesLesseeAbstract_637508060359560312" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent_637508060359560312" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAndLiabilitiesLesseeAbstract_637508060359560312" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent_637508060359560312" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="us-gaap_OperatingLeaseLiability_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAndLiabilitiesLesseeAbstract_637508060359560312" xlink:to="us-gaap_OperatingLeaseLiability_637508060359560312" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAndLiabilitiesLesseeAbstract_637508060359560312" xlink:to="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_637508060359560312" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AssetsAndLiabilitiesLesseeAbstract_637508060359560312" xlink:to="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_637508060359560312" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseCostAbstract" xlink:label="us-gaap_LeaseCostAbstract_637508060359560312" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeasesAbstract" xlink:to="us-gaap_LeaseCostAbstract_637508060359560312" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseCost" xlink:label="us-gaap_OperatingLeaseCost_637508060359570314" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeaseCostAbstract_637508060359560312" xlink:to="us-gaap_OperatingLeaseCost_637508060359570314" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasePayments" xlink:label="us-gaap_OperatingLeasePayments_637508060359570314" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeaseCostAbstract_637508060359560312" xlink:to="us-gaap_OperatingLeasePayments_637508060359570314" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureLeasesUndiscountedCashPaymentObligationsDetails" xlink:type="extended" xlink:title="41103 - Disclosure - Leases - Undiscounted Cash Payment Obligations (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeasesAbstract" xlink:label="us-gaap_LeasesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract" xlink:label="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_LeasesAbstract" xlink:to="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_637508060359570314" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_637508060359570314" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_637508060359570314" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_637508060359570314" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_637508060359620318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_637508060359620318" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_637508060359620318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_637508060359620318" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_637508060359620318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_637508060359620318" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_637508060359620318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_637508060359620318" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_637508060359620318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_637508060359620318" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_637508060359620318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_637508060359620318" order="8" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="9" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="us-gaap_OperatingLeaseLiability_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_OperatingLeaseLiability_637508060359630317" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent_637508060359630317" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="9" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_637508060359570314" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent_637508060359630317" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="8" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCollaborationAndLicensingAgreementsAdditionalInformationDetails" xlink:type="extended" xlink:title="41201 - Disclosure - Collaboration and Licensing Agreements - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsAbstract" xlink:label="ardx_CollaborationAndLicensingAgreementsAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable" xlink:label="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_CollaborationAndLicensingAgreementsAbstract" xlink:to="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_637508060359630317" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_637508060359630317" xlink:to="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_637508060359630317" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfAdoptionMember" xlink:label="us-gaap_TypeOfAdoptionMember_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_637508060359630317" xlink:to="us-gaap_TypeOfAdoptionMember_637508060359630317" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountingStandardsUpdate201409Member" xlink:label="us-gaap_AccountingStandardsUpdate201409Member_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TypeOfAdoptionMember_637508060359630317" xlink:to="us-gaap_AccountingStandardsUpdate201409Member_637508060359630317" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="us-gaap_TypeOfArrangementAxis_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_637508060359630317" xlink:to="us-gaap_TypeOfArrangementAxis_637508060359630317" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TypeOfArrangementAxis_637508060359630317" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_637508060359630317" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_LicenseAgreementMember" xlink:label="ardx_LicenseAgreementMember_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember_637508060359630317" xlink:to="ardx_LicenseAgreementMember_637508060359630317" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DevelopmentAndCommercializationMember" xlink:label="ardx_DevelopmentAndCommercializationMember_637508060359630317" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_LicenseAgreementMember_637508060359630317" xlink:to="ardx_DevelopmentAndCommercializationMember_637508060359630317" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_CounterpartyNameAxis" xlink:label="srt_CounterpartyNameAxis_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_637508060359630317" xlink:to="srt_CounterpartyNameAxis_637508060359640319" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain" xlink:label="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CounterpartyNameAxis_637508060359640319" xlink:to="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359640319" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_KyowaKirinCo.LtdMember" xlink:label="ardx_KyowaKirinCo.LtdMember_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359640319" xlink:to="ardx_KyowaKirinCo.LtdMember_637508060359640319" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_KyowaHakkoKirinMember" xlink:label="ardx_KyowaHakkoKirinMember_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359640319" xlink:to="ardx_KyowaHakkoKirinMember_637508060359640319" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_XuanzhuHkBiopharmaceuticalLimitedOrXuanzhuMember" xlink:label="ardx_XuanzhuHkBiopharmaceuticalLimitedOrXuanzhuMember_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359640319" xlink:to="ardx_XuanzhuHkBiopharmaceuticalLimitedOrXuanzhuMember_637508060359640319" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ShanghaiFosunPharmaceuticalIndustrialDevelopmentMember" xlink:label="ardx_ShanghaiFosunPharmaceuticalIndustrialDevelopmentMember_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359640319" xlink:to="ardx_ShanghaiFosunPharmaceuticalIndustrialDevelopmentMember_637508060359640319" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_XuanzhuHKBiopharmaceuticalLimitedMember" xlink:label="ardx_XuanzhuHKBiopharmaceuticalLimitedMember_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359640319" xlink:to="ardx_XuanzhuHKBiopharmaceuticalLimitedMember_637508060359640319" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AstrazenecaMember" xlink:label="ardx_AstrazenecaMember_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359640319" xlink:to="ardx_AstrazenecaMember_637508060359640319" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_KnightTherapeuticsIncMember" xlink:label="ardx_KnightTherapeuticsIncMember_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359640319" xlink:to="ardx_KnightTherapeuticsIncMember_637508060359640319" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="srt_ProductOrServiceAxis_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_637508060359630317" xlink:to="srt_ProductOrServiceAxis_637508060359640319" order="4" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="srt_ProductsAndServicesDomain_637508060359640319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ProductOrServiceAxis_637508060359640319" xlink:to="srt_ProductsAndServicesDomain_637508060359640319" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProductMember" xlink:label="us-gaap_ProductMember_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ProductsAndServicesDomain_637508060359640319" xlink:to="us-gaap_ProductMember_637508060359650309" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LicenseMember" xlink:label="us-gaap_LicenseMember_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_ProductsAndServicesDomain_637508060359640319" xlink:to="us-gaap_LicenseMember_637508060359650309" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis" xlink:label="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_637508060359630317" xlink:to="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_637508060359650309" order="5" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain" xlink:label="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionAxis_637508060359650309" xlink:to="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_637508060359650309" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member" xlink:label="us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_InitialApplicationPeriodCumulativeEffectTransitionDomain_637508060359650309" xlink:to="us-gaap_DifferenceBetweenRevenueGuidanceInEffectBeforeAndAfterTopic606Member_637508060359650309" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_637508060359630317" xlink:to="srt_RangeAxis_637508060359650309" order="6" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="srt_RangeMember_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeAxis_637508060359650309" xlink:to="srt_RangeMember_637508060359650309" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="srt_MinimumMember_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeMember_637508060359650309" xlink:to="srt_MinimumMember_637508060359650309" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RangeMember_637508060359650309" xlink:to="srt_MaximumMember_637508060359650309" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems" xlink:label="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_637508060359630317" xlink:to="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" order="7" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_NumberOfPreClinicalStudyReadyCompounds" xlink:label="ardx_NumberOfPreClinicalStudyReadyCompounds_637508060359660318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_NumberOfPreClinicalStudyReadyCompounds_637508060359660318" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_NumberOfCompoundInhibitingFirstUndisclosedTarget" xlink:label="ardx_NumberOfCompoundInhibitingFirstUndisclosedTarget_637508060359660318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_NumberOfCompoundInhibitingFirstUndisclosedTarget_637508060359660318" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_NumberOfDevelopmentCandidates" xlink:label="ardx_NumberOfDevelopmentCandidates_637508060359660318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_NumberOfDevelopmentCandidates_637508060359660318" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_NumberOfSeparateCollaborativeAgreements" xlink:label="ardx_NumberOfSeparateCollaborativeAgreements_637508060359660318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_NumberOfSeparateCollaborativeAgreements_637508060359660318" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsUpfrontPaymentReceivable" xlink:label="ardx_CollaborationAndLicensingAgreementsUpfrontPaymentReceivable_637508060359660318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborationAndLicensingAgreementsUpfrontPaymentReceivable_637508060359660318" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsUpfrontPaymentReceivableFistInstallment" xlink:label="ardx_CollaborationAndLicensingAgreementsUpfrontPaymentReceivableFistInstallment_637508060359660318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborationAndLicensingAgreementsUpfrontPaymentReceivableFistInstallment_637508060359660318" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TermOfPaymentOfLicenseFeeFirstInstallment" xlink:label="ardx_TermOfPaymentOfLicenseFeeFirstInstallment_637508060359660318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_TermOfPaymentOfLicenseFeeFirstInstallment_637508060359660318" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsUpfrontPaymentReceivableSecondInstallment" xlink:label="ardx_CollaborationAndLicensingAgreementsUpfrontPaymentReceivableSecondInstallment_637508060359670319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborationAndLicensingAgreementsUpfrontPaymentReceivableSecondInstallment_637508060359670319" order="8" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TermOfAgreement" xlink:label="ardx_TermOfAgreement_637508060359670319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_TermOfAgreement_637508060359670319" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsInitialTransactionPrice" xlink:label="ardx_CollaborationAndLicensingAgreementsInitialTransactionPrice_637508060359670319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborationAndLicensingAgreementsInitialTransactionPrice_637508060359670319" order="10" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_637508060359670319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_637508060359670319" order="11" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="7" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TransactionPriceAllocatedToPartiallyUnsatisfiedPerformanceObligations" xlink:label="ardx_TransactionPriceAllocatedToPartiallyUnsatisfiedPerformanceObligations_637508060359670319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_TransactionPriceAllocatedToPartiallyUnsatisfiedPerformanceObligations_637508060359670319" order="12" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="us-gaap_ContractWithCustomerLiabilityCurrent_637508060359670319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="us-gaap_ContractWithCustomerLiabilityCurrent_637508060359670319" order="13" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromLicenseFeesReceived" xlink:label="us-gaap_ProceedsFromLicenseFeesReceived_637508060359670319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="us-gaap_ProceedsFromLicenseFeesReceived_637508060359670319" order="14" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ContractWithCustomerAssetNetCurrent" xlink:label="us-gaap_ContractWithCustomerAssetNetCurrent_637508060359670319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="us-gaap_ContractWithCustomerAssetNetCurrent_637508060359670319" order="15" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_UnchargedLicenseFeeCurrent" xlink:label="ardx_UnchargedLicenseFeeCurrent_637508060359682390" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_UnchargedLicenseFeeCurrent_637508060359682390" order="16" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborativeArrangementDevelopmentMilestonesPaymentToBeReceived" xlink:label="ardx_CollaborativeArrangementDevelopmentMilestonesPaymentToBeReceived_637508060359682390" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborativeArrangementDevelopmentMilestonesPaymentToBeReceived_637508060359682390" order="17" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborativeArrangementDevelopmentMilestonesPaymentReceived" xlink:label="ardx_CollaborativeArrangementDevelopmentMilestonesPaymentReceived_637508060359682390" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborativeArrangementDevelopmentMilestonesPaymentReceived_637508060359682390" order="18" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborativeArrangementCommercializationMilestonesPaymentToBeReceived" xlink:label="ardx_CollaborativeArrangementCommercializationMilestonesPaymentToBeReceived_637508060359682390" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborativeArrangementCommercializationMilestonesPaymentToBeReceived_637508060359682390" order="19" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsLicenseFee" xlink:label="ardx_CollaborationAndLicensingAgreementsLicenseFee_637508060359682390" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborationAndLicensingAgreementsLicenseFee_637508060359682390" order="20" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsSecondMilestonePayment" xlink:label="ardx_CollaborationAndLicensingAgreementsSecondMilestonePayment_637508060359690452" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborationAndLicensingAgreementsSecondMilestonePayment_637508060359690452" order="21" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborativeArrangementFutureDevelopmentAndCommercializationMilestones" xlink:label="ardx_CollaborativeArrangementFutureDevelopmentAndCommercializationMilestones_637508060359690452" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborativeArrangementFutureDevelopmentAndCommercializationMilestones_637508060359690452" order="22" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_ThresholdPercentageOfSalesForTieredRoyalties" xlink:label="ardx_ThresholdPercentageOfSalesForTieredRoyalties_637508060359690452" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_ThresholdPercentageOfSalesForTieredRoyalties_637508060359690452" order="23" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborativeArrangementUpFrontPaymentAndDevelopmentAndSalesMilestonesPaymentToBeReceived" xlink:label="ardx_CollaborativeArrangementUpFrontPaymentAndDevelopmentAndSalesMilestonesPaymentToBeReceived_637508060359690452" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborativeArrangementUpFrontPaymentAndDevelopmentAndSalesMilestonesPaymentToBeReceived_637508060359690452" order="24" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CollaborationAndLicensingAgreementsPaymentPerTerminationAgreement" xlink:label="ardx_CollaborationAndLicensingAgreementsPaymentPerTerminationAgreement_637508060359690452" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CollaborationAndLicensingAgreementsPaymentPerTerminationAgreement_637508060359690452" order="25" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfRevenue" xlink:label="us-gaap_CostOfRevenue_637508060359700321" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="us-gaap_CostOfRevenue_637508060359700321" order="26" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_CostOfRevenueAggregateAmountRecognized" xlink:label="ardx_CostOfRevenueAggregateAmountRecognized_637508060359700321" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_CostOfRevenueAggregateAmountRecognized_637508060359700321" order="27" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PaymentsOfUnchargedLicenseFees" xlink:label="ardx_PaymentsOfUnchargedLicenseFees_637508060359700321" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_PaymentsOfUnchargedLicenseFees_637508060359700321" order="28" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PaymentsOfUnchargedLicenseFeesAggregateAmountPaid" xlink:label="ardx_PaymentsOfUnchargedLicenseFeesAggregateAmountPaid_637508060359700321" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_PaymentsOfUnchargedLicenseFeesAggregateAmountPaid_637508060359700321" order="29" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PercentageOfRoyaltyRevenue" xlink:label="ardx_PercentageOfRoyaltyRevenue_637508060359700321" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_PercentageOfRoyaltyRevenue_637508060359700321" order="30" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PercentageOfNonRoyaltyRevenue" xlink:label="ardx_PercentageOfNonRoyaltyRevenue_637508060359710323" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="ardx_PercentageOfNonRoyaltyRevenue_637508060359710323" order="31" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesNoncurrent" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesNoncurrent_637508060359710323" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_637508060359650309" xlink:to="us-gaap_AccountsPayableAndAccruedLiabilitiesNoncurrent_637508060359710323" order="32" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="6" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureIncomeTaxesDetails" xlink:type="extended" xlink:title="41301 - Disclosure - Income Taxes - (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="us-gaap_IncomeTaxDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_637508060359710323" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_637508060359710323" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_637508060359710323" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_637508060359710323" xlink:to="us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_637508060359710323" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:label="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_637508060359710323" xlink:to="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_637508060359720303" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CurrentForeignTaxExpenseBenefit" xlink:label="us-gaap_CurrentForeignTaxExpenseBenefit_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_637508060359710323" xlink:to="us-gaap_CurrentForeignTaxExpenseBenefit_637508060359720303" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:label="us-gaap_CurrentIncomeTaxExpenseBenefit_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_637508060359710323" xlink:to="us-gaap_CurrentIncomeTaxExpenseBenefit_637508060359720303" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_637508060359710323" xlink:to="us-gaap_IncomeTaxExpenseBenefit_637508060359720303" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="5" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureIncomeTaxesReconciliationOfStatutoryFederalIncomeTaxRateToCompanySEffectiveTaxRateDetails" xlink:type="extended" xlink:title="41302 - Disclosure - Income Taxes - Reconciliation of Statutory Federal Income Tax Rate to the Company's Effective Tax Rate (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="us-gaap_IncomeTaxDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_637508060359720303" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_637508060359720303" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxCredits" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationTaxCredits_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationTaxCredits_637508060359720303" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_637508060359720303" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost_637508060359720303" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_637508060359720303" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_637508060359720303" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_EffectiveIncomeTaxRateContinuingOperations_637508060359720303" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureIncomeTaxesSignificantComponentsOfCompanySDeferredTaxAssetsDetails" xlink:type="extended" xlink:title="41303 - Disclosure - Income Taxes - Significant Components of the Company's Deferred Tax Assets (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="us-gaap_IncomeTaxDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsNetAbstract" xlink:label="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DeferredTaxAssetsAmortizationAndDepreciation" xlink:label="ardx_DeferredTaxAssetsAmortizationAndDepreciation_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" xlink:to="ardx_DeferredTaxAssetsAmortizationAndDepreciation_637508060359730319" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" xlink:to="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_637508060359730319" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch" xlink:label="us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" xlink:to="us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsResearch_637508060359730319" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost_637508060359730319" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DeferredTaxAssetsLeaseObligation" xlink:label="ardx_DeferredTaxAssetsLeaseObligation_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" xlink:to="ardx_DeferredTaxAssetsLeaseObligation_637508060359730319" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsOther" xlink:label="us-gaap_DeferredTaxAssetsOther_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" xlink:to="us-gaap_DeferredTaxAssetsOther_637508060359730319" order="6" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsGross" xlink:label="us-gaap_DeferredTaxAssetsGross_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" xlink:to="us-gaap_DeferredTaxAssetsGross_637508060359730319" order="7" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance_637508060359730319" order="8" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsNet" xlink:label="us-gaap_DeferredTaxAssetsNet_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxAssetsNetAbstract_637508060359730319" xlink:to="us-gaap_DeferredTaxAssetsNet_637508060359730319" order="9" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNetAbstract" xlink:label="us-gaap_DeferredTaxLiabilitiesNetAbstract_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_DeferredTaxLiabilitiesNetAbstract_637508060359730319" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DeferredTaxLiabilitiesRightOfUseAsset" xlink:label="ardx_DeferredTaxLiabilitiesRightOfUseAsset_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxLiabilitiesNetAbstract_637508060359730319" xlink:to="ardx_DeferredTaxLiabilitiesRightOfUseAsset_637508060359730319" order="1" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_DeferredTaxLiabilitiesRevenueRecognition" xlink:label="ardx_DeferredTaxLiabilitiesRevenueRecognition_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxLiabilitiesNetAbstract_637508060359730319" xlink:to="ardx_DeferredTaxLiabilitiesRevenueRecognition_637508060359730319" order="2" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOther" xlink:label="us-gaap_DeferredTaxLiabilitiesOther_637508060359730319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_DeferredTaxLiabilitiesNetAbstract_637508060359730319" xlink:to="us-gaap_DeferredTaxLiabilitiesOther_637508060359730319" order="3" use="optional" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxDisclosureAbstract" xlink:to="us-gaap_DeferredTaxAssetsLiabilitiesNet_637508060359740319" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/totalLabel" priority="4" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureIncomeTaxesAdditionalInformationDetails" xlink:type="extended" xlink:title="41304 - Disclosure - Income Taxes - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="IncomeTaxDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IncomeTaxDisclosureTable" xlink:label="ardx_IncomeTaxDisclosureTable_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="ardx_IncomeTaxDisclosureTable_637508060359740319" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="us-gaap_IncomeTaxAuthorityAxis_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_IncomeTaxDisclosureTable_637508060359740319" xlink:to="us-gaap_IncomeTaxAuthorityAxis_637508060359740319" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="us-gaap_IncomeTaxAuthorityDomain_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxAuthorityAxis_637508060359740319" xlink:to="us-gaap_IncomeTaxAuthorityDomain_637508060359740319" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DomesticCountryMember" xlink:label="us-gaap_DomesticCountryMember_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxAuthorityDomain_637508060359740319" xlink:to="us-gaap_DomesticCountryMember_637508060359740319" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="us-gaap_StateAndLocalJurisdictionMember_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxAuthorityDomain_637508060359740319" xlink:to="us-gaap_StateAndLocalJurisdictionMember_637508060359740319" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignCountryMember" xlink:label="us-gaap_ForeignCountryMember_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_IncomeTaxAuthorityDomain_637508060359740319" xlink:to="us-gaap_ForeignCountryMember_637508060359740319" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxCreditCarryforwardAxis" xlink:label="us-gaap_TaxCreditCarryforwardAxis_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_IncomeTaxDisclosureTable_637508060359740319" xlink:to="us-gaap_TaxCreditCarryforwardAxis_637508060359740319" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxCreditCarryforwardNameDomain" xlink:label="us-gaap_TaxCreditCarryforwardNameDomain_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TaxCreditCarryforwardAxis_637508060359740319" xlink:to="us-gaap_TaxCreditCarryforwardNameDomain_637508060359740319" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ResearchMember" xlink:label="us-gaap_ResearchMember_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TaxCreditCarryforwardNameDomain_637508060359740319" xlink:to="us-gaap_ResearchMember_637508060359740319" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_MinimumTaxCreditCarryforwardMember" xlink:label="ardx_MinimumTaxCreditCarryforwardMember_637508060359740319" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TaxCreditCarryforwardNameDomain_637508060359740319" xlink:to="ardx_MinimumTaxCreditCarryforwardMember_637508060359740319" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis_637508060359750318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_IncomeTaxDisclosureTable_637508060359740319" xlink:to="srt_StatementGeographicalAxis_637508060359750318" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_637508060359750318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis_637508060359750318" xlink:to="srt_SegmentGeographicalDomain_637508060359750318" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd#stpr_CA" xlink:label="stpr_CA_637508060359750318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_SegmentGeographicalDomain_637508060359750318" xlink:to="stpr_CA_637508060359750318" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_IncomeTaxDisclosureLineItems" xlink:label="ardx_IncomeTaxDisclosureLineItems_637508060359750318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_IncomeTaxDisclosureTable_637508060359740319" xlink:to="ardx_IncomeTaxDisclosureLineItems_637508060359750318" order="4" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_637508060359750318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_IncomeTaxDisclosureLineItems_637508060359750318" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_637508060359750318" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="6" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="us-gaap_OperatingLossCarryforwards_637508060359750318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_IncomeTaxDisclosureLineItems_637508060359750318" xlink:to="us-gaap_OperatingLossCarryforwards_637508060359750318" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_OperatingLossCarryforwardsWithoutExpiration" xlink:label="ardx_OperatingLossCarryforwardsWithoutExpiration_637508060359750318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_IncomeTaxDisclosureLineItems_637508060359750318" xlink:to="ardx_OperatingLossCarryforwardsWithoutExpiration_637508060359750318" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TaxCreditCarryforwardAmount" xlink:label="us-gaap_TaxCreditCarryforwardAmount_637508060359750318" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="ardx_IncomeTaxDisclosureLineItems_637508060359750318" xlink:to="us-gaap_TaxCreditCarryforwardAmount_637508060359750318" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureIncomeTaxesReconciliationOfBeginningAndEndingAmountOfUnrecognizedTaxBenefitsDetails" xlink:type="extended" xlink:title="41305 - Disclosure - Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="IncomeTaxDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="us-gaap_UnrecognizedTaxBenefits_637508060359760331" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="us-gaap_UnrecognizedTaxBenefits_637508060359760331" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_UnrecognizedTaxBenefitsIncreaseDecreasesResultingFromPriorPeriodTaxPositions" xlink:label="ardx_UnrecognizedTaxBenefitsIncreaseDecreasesResultingFromPriorPeriodTaxPositions_637508060359760331" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="ardx_UnrecognizedTaxBenefitsIncreaseDecreasesResultingFromPriorPeriodTaxPositions_637508060359760331" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions_637508060359760331" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions_637508060359760331" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="us-gaap_UnrecognizedTaxBenefits_6375080603597603311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="us-gaap_UnrecognizedTaxBenefits_6375080603597603311" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:label="us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_637508060359760331" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="IncomeTaxDisclosureAbstract" xlink:to="us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_637508060359760331" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureGeographicInformationAndConcentrationsDetails" xlink:type="extended" xlink:title="41401 - Disclosure - Geographic Information and Concentrations (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentsGeographicalAreasAbstract" xlink:label="us-gaap_SegmentsGeographicalAreasAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:label="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SegmentsGeographicalAreasAbstract" xlink:to="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_637508060359770311" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_CounterpartyNameAxis" xlink:label="srt_CounterpartyNameAxis_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_637508060359770311" xlink:to="srt_CounterpartyNameAxis_637508060359770311" order="1" use="optional" priority="3" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain" xlink:label="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CounterpartyNameAxis_637508060359770311" xlink:to="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359770311" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_KkcMember" xlink:label="ardx_KkcMember_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359770311" xlink:to="ardx_KkcMember_637508060359770311" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_637508060359770311" xlink:to="srt_StatementGeographicalAxis_637508060359770311" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_StatementGeographicalAxis_637508060359770311" xlink:to="srt_SegmentGeographicalDomain_637508060359770311" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NonUsMember" xlink:label="us-gaap_NonUsMember_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_SegmentGeographicalDomain_637508060359770311" xlink:to="us-gaap_NonUsMember_637508060359770311" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_NorthAmericaMember" xlink:label="srt_NorthAmericaMember_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NonUsMember_637508060359770311" xlink:to="srt_NorthAmericaMember_637508060359770311" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_AsiaPacificMember" xlink:label="srt_AsiaPacificMember_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NonUsMember_637508060359770311" xlink:to="srt_AsiaPacificMember_637508060359770311" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_JP" xlink:label="country_JP_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_SegmentGeographicalDomain_637508060359770311" xlink:to="country_JP_637508060359770311" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_HK" xlink:label="country_HK_637508060359770311" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_SegmentGeographicalDomain_637508060359770311" xlink:to="country_HK_637508060359770311" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd#country_CN" xlink:label="country_CN_637508060359782013" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_SegmentGeographicalDomain_637508060359770311" xlink:to="country_CN_637508060359782013" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_TypeOfArrangementAxis" xlink:label="us-gaap_TypeOfArrangementAxis_637508060359782013" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_637508060359770311" xlink:to="us-gaap_TypeOfArrangementAxis_637508060359782013" order="3" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_637508060359782013" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_TypeOfArrangementAxis_637508060359782013" xlink:to="us-gaap_ArrangementsAndNonarrangementTransactionsMember_637508060359782013" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_TwoThousandSeventeenAndTwoThousandNineteenKKCAgreementMember" xlink:label="ardx_TwoThousandSeventeenAndTwoThousandNineteenKKCAgreementMember_637508060359782013" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ArrangementsAndNonarrangementTransactionsMember_637508060359782013" xlink:to="ardx_TwoThousandSeventeenAndTwoThousandNineteenKKCAgreementMember_637508060359782013" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems" xlink:label="us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_637508060359782013" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_637508060359770311" xlink:to="us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_637508060359782013" order="4" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_637508060359782013" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_637508060359782013" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_637508060359782013" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="6" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureGeographicInformationAndConcentrationsConcentrationRiskDetails" xlink:type="extended" xlink:title="41402 - Disclosure - Geographic Information and Concentrations - Concentration Risk (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentsGeographicalAreasAbstract" xlink:label="us-gaap_SegmentsGeographicalAreasAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskTable" xlink:label="us-gaap_ConcentrationRiskTable_637508060359782013" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_SegmentsGeographicalAreasAbstract" xlink:to="us-gaap_ConcentrationRiskTable_637508060359782013" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_CounterpartyNameAxis" xlink:label="srt_CounterpartyNameAxis_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ConcentrationRiskTable_637508060359782013" xlink:to="srt_CounterpartyNameAxis_637508060359790310" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain" xlink:label="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_CounterpartyNameAxis_637508060359790310" xlink:to="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359790310" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_KkcMember" xlink:label="ardx_KkcMember_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359790310" xlink:to="ardx_KkcMember_637508060359790310" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_KnightTherapeuticsIncMember" xlink:label="ardx_KnightTherapeuticsIncMember_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359790310" xlink:to="ardx_KnightTherapeuticsIncMember_637508060359790310" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_FosunMember" xlink:label="ardx_FosunMember_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359790310" xlink:to="ardx_FosunMember_637508060359790310" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_XuanzhuMember" xlink:label="ardx_XuanzhuMember_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain_637508060359790310" xlink:to="ardx_XuanzhuMember_637508060359790310" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskLineItems" xlink:label="us-gaap_ConcentrationRiskLineItems_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ConcentrationRiskTable_637508060359782013" xlink:to="us-gaap_ConcentrationRiskLineItems_637508060359790310" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="us-gaap_ConcentrationRiskPercentage1_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ConcentrationRiskLineItems_637508060359790310" xlink:to="us-gaap_ConcentrationRiskPercentage1_637508060359790310" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureNetLossPerShareComputationOfBasicAndDilutedLossPerShareAttributableToCommonStockholdersDetails" xlink:type="extended" xlink:title="41501 - Disclosure - Net Loss Per Share - Computation of Basic and Diluted Loss Per Share Attributable to Common Stockholders (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="EarningsPerShareAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLossAbstract" xlink:label="us-gaap_NetIncomeLossAbstract_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="EarningsPerShareAbstract" xlink:to="us-gaap_NetIncomeLossAbstract_637508060359790310" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_637508060359790310" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_NetIncomeLossAbstract_637508060359790310" xlink:to="us-gaap_NetIncomeLoss_637508060359790310" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="EarningsPerShareAbstract" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_637508060359800294" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted" xlink:label="us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_637508060359800294" xlink:to="us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted_637508060359800294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareBasicAndDiluted" xlink:label="us-gaap_EarningsPerShareBasicAndDiluted_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="EarningsPerShareAbstract" xlink:to="us-gaap_EarningsPerShareBasicAndDiluted_637508060359800294" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/positiveLabel" priority="2" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureNetLossPerShareAdditionalInformationDetails" xlink:type="extended" xlink:title="41502 - Disclosure - Net Loss Per Share - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="EarningsPerShareAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="EarningsPerShareAbstract" xlink:to="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_637508060359800294" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_637508060359800294" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_637508060359800294" order="1" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_637508060359800294" xlink:to="us-gaap_AntidilutiveSecuritiesNameDomain_637508060359800294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="us-gaap_EmployeeStockOptionMember_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain_637508060359800294" xlink:to="us-gaap_EmployeeStockOptionMember_637508060359800294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_WarrantsToPurchaseCommonStockMember" xlink:label="ardx_WarrantsToPurchaseCommonStockMember_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain_637508060359800294" xlink:to="ardx_WarrantsToPurchaseCommonStockMember_637508060359800294" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember" xlink:label="us-gaap_RestrictedStockUnitsRSUMember_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain_637508060359800294" xlink:to="us-gaap_RestrictedStockUnitsRSUMember_637508060359800294" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_PerformanceBasedRestrictedStockUnitsMember" xlink:label="ardx_PerformanceBasedRestrictedStockUnitsMember_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain_637508060359800294" xlink:to="ardx_PerformanceBasedRestrictedStockUnitsMember_637508060359800294" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_EmployeeStockPurchasePlanMember" xlink:label="ardx_EmployeeStockPurchasePlanMember_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain_637508060359800294" xlink:to="ardx_EmployeeStockPurchasePlanMember_637508060359800294" order="5" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_637508060359800294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_637508060359800294" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_637508060359800294" order="2" use="optional" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_637508060359810293" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_637508060359800294" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_637508060359810293" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="ardx-20201231.xsd#ardx_AntidilutiveSecuritiesIncludedFromComputationOfEarningsPerShareAmount" xlink:label="ardx_AntidilutiveSecuritiesIncludedFromComputationOfEarningsPerShareAmount_637508060359810293" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_637508060359800294" xlink:to="ardx_AntidilutiveSecuritiesIncludedFromComputationOfEarningsPerShareAmount_637508060359810293" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="1" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureCommitmentsAndContingenciesAdditionalInformationDetails" xlink:type="extended" xlink:title="41601 - Disclosure - Commitments and Contingencies - Additional Information (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LossContingencyAccrualAtCarryingValue" xlink:label="us-gaap_LossContingencyAccrualAtCarryingValue_637508060359810293" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_CommitmentsAndContingenciesDisclosureAbstract" xlink:to="us-gaap_LossContingencyAccrualAtCarryingValue_637508060359810293" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="3" />
  </presentationLink>
  <presentationLink xlink:role="http://www.ardelyx.com/role/DisclosureSelectedQuarterlyFinancialDataUnauditedScheduleOfSelectedQuarterlyFinancialResultsFromOperationsDetails" xlink:type="extended" xlink:title="41701 - Disclosure - Selected Quarterly Financial Data (Unaudited) - Schedule of Selected Quarterly Financial Results from Operations (Details)">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_QuarterlyFinancialInformationDisclosureAbstract" xlink:label="QuarterlyFinancialInformationDisclosureAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_637508060359810293" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="QuarterlyFinancialInformationDisclosureAbstract" xlink:to="us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_637508060359810293" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="us-gaap_CostsAndExpenses_637508060359810293" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="QuarterlyFinancialInformationDisclosureAbstract" xlink:to="us-gaap_CostsAndExpenses_637508060359810293" order="2" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_637508060359820294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="QuarterlyFinancialInformationDisclosureAbstract" xlink:to="us-gaap_NetIncomeLoss_637508060359820294" order="3" use="optional" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel" priority="4" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareBasicAndDilutedAbstract" xlink:label="us-gaap_EarningsPerShareBasicAndDilutedAbstract_637508060359820294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="QuarterlyFinancialInformationDisclosureAbstract" xlink:to="us-gaap_EarningsPerShareBasicAndDilutedAbstract_637508060359820294" order="4" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareBasicAndDiluted" xlink:label="us-gaap_EarningsPerShareBasicAndDiluted_637508060359820294" />
    <presentationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="us-gaap_EarningsPerShareBasicAndDilutedAbstract_637508060359820294" xlink:to="us-gaap_EarningsPerShareBasicAndDiluted_637508060359820294" order="1" use="optional" preferredLabel="http://www.xbrl.org/2003/role/terseLabel" priority="2" />
  </presentationLink>
</linkbase>
