<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:55b49626-e7f1-400f-8a34-37e828e7ca79,g:3944a7fa-d7ec-4ef2-b9dc-56ae9474db91-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://www.ardelyx.com/role/Cover" xlink:type="simple" xlink:href="ardx-20210630.xsd#Cover"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract_379319fc-7ea5-4c3b-8d3a-a5e94d82f39a" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_CoverAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressesTable_4e2d5126-09ff-42be-8ba3-6b31faeb635c" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressesTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_379319fc-7ea5-4c3b-8d3a-a5e94d82f39a" xlink:to="loc_dei_EntityAddressesTable_4e2d5126-09ff-42be-8ba3-6b31faeb635c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressesAddressTypeAxis_b6059059-d215-4c85-9918-572d65b4d613" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressesAddressTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesTable_4e2d5126-09ff-42be-8ba3-6b31faeb635c" xlink:to="loc_dei_EntityAddressesAddressTypeAxis_b6059059-d215-4c85-9918-572d65b4d613" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AddressTypeDomain_ad4d8fe4-b80c-4461-a69c-0d4572ddf729" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_AddressTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesAddressTypeAxis_b6059059-d215-4c85-9918-572d65b4d613" xlink:to="loc_dei_AddressTypeDomain_ad4d8fe4-b80c-4461-a69c-0d4572ddf729" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_OtherAddressMember_1dd984db-5246-4bd8-91e2-e5f1b49f3b90" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_OtherAddressMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_AddressTypeDomain_ad4d8fe4-b80c-4461-a69c-0d4572ddf729" xlink:to="loc_dei_OtherAddressMember_1dd984db-5246-4bd8-91e2-e5f1b49f3b90" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressesLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesTable_4e2d5126-09ff-42be-8ba3-6b31faeb635c" xlink:to="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_9e51c9f5-4ba8-4c37-ac48-20c2e7259bf3" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentType"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_DocumentType_9e51c9f5-4ba8-4c37-ac48-20c2e7259bf3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_282d17fe-ef1e-4c8a-a798-2627277ae92c" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentQuarterlyReport"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_DocumentQuarterlyReport_282d17fe-ef1e-4c8a-a798-2627277ae92c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_cefd05d1-cb8d-4a3a-822b-2d606dfddb99" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentPeriodEndDate"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_DocumentPeriodEndDate_cefd05d1-cb8d-4a3a-822b-2d606dfddb99" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_fd68225f-5b44-4b12-98f9-036e28121a5b" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentTransitionReport"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_DocumentTransitionReport_fd68225f-5b44-4b12-98f9-036e28121a5b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_00a4e677-6b24-4c5b-9735-f78421f1bf6c" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityFileNumber"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityFileNumber_00a4e677-6b24-4c5b-9735-f78421f1bf6c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_d6399590-98b0-42f3-9826-80dcaee66399" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityRegistrantName"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityRegistrantName_d6399590-98b0-42f3-9826-80dcaee66399" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_fa820154-3775-49a5-8673-3bb01f6de0d2" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityCentralIndexKey"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityCentralIndexKey_fa820154-3775-49a5-8673-3bb01f6de0d2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_1ca8a62e-ecc1-4a05-9470-98252b4c4e00" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_CurrentFiscalYearEndDate_1ca8a62e-ecc1-4a05-9470-98252b4c4e00" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_2486d1b1-bd9e-44ef-b833-545eb424c4c3" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentFiscalYearFocus"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_DocumentFiscalYearFocus_2486d1b1-bd9e-44ef-b833-545eb424c4c3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_50da7561-1c7e-4719-b0fd-c8309c825eb0" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_DocumentFiscalPeriodFocus_50da7561-1c7e-4719-b0fd-c8309c825eb0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_03a84c49-4a1f-4db0-bb74-d6963e222fed" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_AmendmentFlag"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_AmendmentFlag_03a84c49-4a1f-4db0-bb74-d6963e222fed" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_efff80a0-ba35-4837-91dd-11ab293a5562" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:presentationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityIncorporationStateCountryCode_efff80a0-ba35-4837-91dd-11ab293a5562" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_732a4185-5ec3-4b7c-8fef-09b32335f326" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:presentationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityTaxIdentificationNumber_732a4185-5ec3-4b7c-8fef-09b32335f326" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_5bc294ed-3e28-4790-8289-17128e02db1d" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressAddressLine1"/>
    <link:presentationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityAddressAddressLine1_5bc294ed-3e28-4790-8289-17128e02db1d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine2_9d7b8f49-7477-4773-a1bb-2e200a969e5d" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressAddressLine2"/>
    <link:presentationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityAddressAddressLine2_9d7b8f49-7477-4773-a1bb-2e200a969e5d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_a35b8e35-ec2b-4126-ad0f-95ece2994bd8" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressCityOrTown"/>
    <link:presentationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityAddressCityOrTown_a35b8e35-ec2b-4126-ad0f-95ece2994bd8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_817b6f2b-b590-4ed4-b434-d27a9fcc1ae1" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressStateOrProvince"/>
    <link:presentationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityAddressStateOrProvince_817b6f2b-b590-4ed4-b434-d27a9fcc1ae1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_84ef2d36-6408-46f5-aa01-a40472da3c06" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityAddressPostalZipCode"/>
    <link:presentationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityAddressPostalZipCode_84ef2d36-6408-46f5-aa01-a40472da3c06" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_85230d47-39b0-4af9-96bb-6445dbfbaaaa" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_CityAreaCode"/>
    <link:presentationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_CityAreaCode_85230d47-39b0-4af9-96bb-6445dbfbaaaa" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_7b1b8742-5843-47d3-8bf2-0297f270d540" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_LocalPhoneNumber"/>
    <link:presentationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_LocalPhoneNumber_7b1b8742-5843-47d3-8bf2-0297f270d540" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_33cfe46e-7d13-41eb-8a3b-12b7f781309f" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_Security12bTitle"/>
    <link:presentationArc order="21" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_Security12bTitle_33cfe46e-7d13-41eb-8a3b-12b7f781309f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_390ece83-8686-4ff7-99ff-a1b621133e92" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_TradingSymbol"/>
    <link:presentationArc order="22" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_TradingSymbol_390ece83-8686-4ff7-99ff-a1b621133e92" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_90e9b2da-648a-4338-bb70-debef7209735" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_SecurityExchangeName"/>
    <link:presentationArc order="23" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_SecurityExchangeName_90e9b2da-648a-4338-bb70-debef7209735" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_02407c21-212b-4364-b836-fdb591e1222d" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityCurrentReportingStatus"/>
    <link:presentationArc order="24" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityCurrentReportingStatus_02407c21-212b-4364-b836-fdb591e1222d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_d4523b96-0d37-4454-9b58-70de978c0e98" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:presentationArc order="25" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityInteractiveDataCurrent_d4523b96-0d37-4454-9b58-70de978c0e98" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_85b63b0a-3e1e-402f-bbf1-f1961d8f8192" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityFilerCategory"/>
    <link:presentationArc order="26" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityFilerCategory_85b63b0a-3e1e-402f-bbf1-f1961d8f8192" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_222f90b8-b835-4c6a-819d-95c3d729dc2a" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntitySmallBusiness"/>
    <link:presentationArc order="27" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntitySmallBusiness_222f90b8-b835-4c6a-819d-95c3d729dc2a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_125325b6-0ed1-4c38-968e-22a298e378de" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:presentationArc order="28" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityEmergingGrowthCompany_125325b6-0ed1-4c38-968e-22a298e378de" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_e3d3cd41-80d3-414d-8d99-1b5f204cf448" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityShellCompany"/>
    <link:presentationArc order="29" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityShellCompany_e3d3cd41-80d3-414d-8d99-1b5f204cf448" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_81e902a1-a44b-4524-baaf-c9cfc801857f" xlink:href="https://xbrl.sec.gov/dei/2021/dei-2021.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:presentationArc order="30" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_EntityAddressesLineItems_d704256e-b838-439d-8252-4bdf822d5db9" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_81e902a1-a44b-4524-baaf-c9cfc801857f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CONDENSEDBALANCESHEETS" xlink:type="simple" xlink:href="ardx-20210630.xsd#CONDENSEDBALANCESHEETS"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CONDENSEDBALANCESHEETS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_b2c6ed95-5ff6-4d53-91c5-d1f174562484" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_1e66cf8c-8f02-49f8-8792-cfeb87b262b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_b2c6ed95-5ff6-4d53-91c5-d1f174562484" xlink:to="loc_us-gaap_AssetsAbstract_1e66cf8c-8f02-49f8-8792-cfeb87b262b7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_61d1e9ff-d930-45a0-a9f8-2bf700f5031e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_1e66cf8c-8f02-49f8-8792-cfeb87b262b7" xlink:to="loc_us-gaap_AssetsCurrentAbstract_61d1e9ff-d930-45a0-a9f8-2bf700f5031e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2629d6ad-d963-410b-b43a-a24003323b68" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_61d1e9ff-d930-45a0-a9f8-2bf700f5031e" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_2629d6ad-d963-410b-b43a-a24003323b68" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_c961a828-8356-4b43-9bcc-7adddfa0ca8f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_61d1e9ff-d930-45a0-a9f8-2bf700f5031e" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_c961a828-8356-4b43-9bcc-7adddfa0ca8f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_f361b62a-2ed6-4d27-8bdb-f8cd2e437c7d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_61d1e9ff-d930-45a0-a9f8-2bf700f5031e" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_f361b62a-2ed6-4d27-8bdb-f8cd2e437c7d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_902afe71-e249-4f20-9d70-f37383e27aeb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsCurrent"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_61d1e9ff-d930-45a0-a9f8-2bf700f5031e" xlink:to="loc_us-gaap_AssetsCurrent_902afe71-e249-4f20-9d70-f37383e27aeb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_79bdd241-6fb6-4af6-b7ed-83bace027879" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_1e66cf8c-8f02-49f8-8792-cfeb87b262b7" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_79bdd241-6fb6-4af6-b7ed-83bace027879" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermInvestments_3bfa6d8f-d8ad-460a-8f5e-bc7f0c1f660a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermInvestments"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_1e66cf8c-8f02-49f8-8792-cfeb87b262b7" xlink:to="loc_us-gaap_LongTermInvestments_3bfa6d8f-d8ad-460a-8f5e-bc7f0c1f660a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_225a84d0-be31-4b70-932d-172649f950d3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_1e66cf8c-8f02-49f8-8792-cfeb87b262b7" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_225a84d0-be31-4b70-932d-172649f950d3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_688a9718-adb2-4240-a183-b3047bbe8eb3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_1e66cf8c-8f02-49f8-8792-cfeb87b262b7" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_688a9718-adb2-4240-a183-b3047bbe8eb3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_85b56109-2285-490d-96f4-9c2ea4333be9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_1e66cf8c-8f02-49f8-8792-cfeb87b262b7" xlink:to="loc_us-gaap_Assets_85b56109-2285-490d-96f4-9c2ea4333be9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_b2c6ed95-5ff6-4d53-91c5-d1f174562484" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_ca79326e-4cb2-4504-ac16-0649ee9681f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_ca79326e-4cb2-4504-ac16-0649ee9681f3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_2b604093-aa89-470b-afa0-bfd2f55728dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_ca79326e-4cb2-4504-ac16-0649ee9681f3" xlink:to="loc_us-gaap_AccountsPayableCurrent_2b604093-aa89-470b-afa0-bfd2f55728dd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_93b7388f-d6c8-4277-913e-676adf552feb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_ca79326e-4cb2-4504-ac16-0649ee9681f3" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_93b7388f-d6c8-4277-913e-676adf552feb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_4477b4c9-e601-49ac-a213-8f483b888a62" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_ca79326e-4cb2-4504-ac16-0649ee9681f3" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_4477b4c9-e601-49ac-a213-8f483b888a62" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansPayableCurrent_b19f369a-9cd9-4b4f-90fa-8bcc04e19f79" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansPayableCurrent"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_ca79326e-4cb2-4504-ac16-0649ee9681f3" xlink:to="loc_us-gaap_LoansPayableCurrent_b19f369a-9cd9-4b4f-90fa-8bcc04e19f79" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_e2c490cc-a00b-4838-81f3-3a9c36ed10c2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_ca79326e-4cb2-4504-ac16-0649ee9681f3" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_e2c490cc-a00b-4838-81f3-3a9c36ed10c2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilities_e4adc4a6-b04e-42f9-8ada-2967a011ba92" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilities"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_ca79326e-4cb2-4504-ac16-0649ee9681f3" xlink:to="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilities_e4adc4a6-b04e-42f9-8ada-2967a011ba92" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_40196dc8-ddbb-44cd-8745-9e9821a5d97e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_ca79326e-4cb2-4504-ac16-0649ee9681f3" xlink:to="loc_us-gaap_LiabilitiesCurrent_40196dc8-ddbb-44cd-8745-9e9821a5d97e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_e69ce3bd-5411-4aa0-97f0-1befa4ca5015" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_e69ce3bd-5411-4aa0-97f0-1befa4ca5015" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermLoansPayable_ca5d6ecd-ba62-4971-b9de-ce87a46d89d1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermLoansPayable"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:to="loc_us-gaap_LongTermLoansPayable_ca5d6ecd-ba62-4971-b9de-ce87a46d89d1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_4e6f9f1e-f470-4494-9abb-0a537967be0f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_4e6f9f1e-f470-4494-9abb-0a537967be0f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_3214e9b3-289e-416e-bc4b-b7b62d68cca6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Liabilities"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:to="loc_us-gaap_Liabilities_3214e9b3-289e-416e-bc4b-b7b62d68cca6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_5e2c208b-5537-4731-8744-9309cacff670" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:to="loc_us-gaap_CommitmentsAndContingencies_5e2c208b-5537-4731-8744-9309cacff670" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_2cff1fa5-9e58-4bc3-85e1-a1ef1a194d20" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:to="loc_us-gaap_StockholdersEquityAbstract_2cff1fa5-9e58-4bc3-85e1-a1ef1a194d20" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_e503eed3-f2c2-4766-bd94-64e50efdc1f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockValue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_2cff1fa5-9e58-4bc3-85e1-a1ef1a194d20" xlink:to="loc_us-gaap_PreferredStockValue_e503eed3-f2c2-4766-bd94-64e50efdc1f7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_ea2e73c5-93ce-4834-a55d-fa4d45073f02" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockValue"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_2cff1fa5-9e58-4bc3-85e1-a1ef1a194d20" xlink:to="loc_us-gaap_CommonStockValue_ea2e73c5-93ce-4834-a55d-fa4d45073f02" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_e5f4f3a8-c78a-4a8b-b677-68b89ad5430f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_2cff1fa5-9e58-4bc3-85e1-a1ef1a194d20" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_e5f4f3a8-c78a-4a8b-b677-68b89ad5430f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_b3c3f0ac-919c-4e90-82f4-c307254cd4b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_2cff1fa5-9e58-4bc3-85e1-a1ef1a194d20" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_b3c3f0ac-919c-4e90-82f4-c307254cd4b5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_9e7ee595-75b7-41ae-af26-59db8dc528b0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_2cff1fa5-9e58-4bc3-85e1-a1ef1a194d20" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_9e7ee595-75b7-41ae-af26-59db8dc528b0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_f075a662-23c8-40d5-be61-7ce6e7030cd9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_2cff1fa5-9e58-4bc3-85e1-a1ef1a194d20" xlink:to="loc_us-gaap_StockholdersEquity_f075a662-23c8-40d5-be61-7ce6e7030cd9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_bf72c0ca-41ce-4126-877a-b620a509f461" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_2e6e4ce9-f61c-43cb-9842-19f93279683b" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_bf72c0ca-41ce-4126-877a-b620a509f461" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CONDENSEDBALANCESHEETSParenthetical" xlink:type="simple" xlink:href="ardx-20210630.xsd#CONDENSEDBALANCESHEETSParenthetical"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CONDENSEDBALANCESHEETSParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_1c71659f-fd5f-4b74-96d2-b81c2f7c49be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementOfFinancialPositionAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_d0f44233-2e07-4e62-bbba-96e918c11616" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_1c71659f-fd5f-4b74-96d2-b81c2f7c49be" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_d0f44233-2e07-4e62-bbba-96e918c11616" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_d69c333d-4eeb-4b3b-9e13-640ffbb5159a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_1c71659f-fd5f-4b74-96d2-b81c2f7c49be" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_d69c333d-4eeb-4b3b-9e13-640ffbb5159a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_f47b3b56-a7e6-4e65-952d-34c18dba0621" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_1c71659f-fd5f-4b74-96d2-b81c2f7c49be" xlink:to="loc_us-gaap_PreferredStockSharesIssued_f47b3b56-a7e6-4e65-952d-34c18dba0621" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_040d41cd-455e-40ea-a6fe-7b19f6b93292" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_1c71659f-fd5f-4b74-96d2-b81c2f7c49be" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_040d41cd-455e-40ea-a6fe-7b19f6b93292" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_ef6f498c-9dfc-4be9-b500-87590ed1e719" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_1c71659f-fd5f-4b74-96d2-b81c2f7c49be" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_ef6f498c-9dfc-4be9-b500-87590ed1e719" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_74ac09f3-1b52-48a7-bbb2-e4ebeb557135" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_1c71659f-fd5f-4b74-96d2-b81c2f7c49be" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_74ac09f3-1b52-48a7-bbb2-e4ebeb557135" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_361ea0fb-30f6-410a-a30f-f391636f3a1a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_1c71659f-fd5f-4b74-96d2-b81c2f7c49be" xlink:to="loc_us-gaap_CommonStockSharesIssued_361ea0fb-30f6-410a-a30f-f391636f3a1a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_ec30cad8-7093-4c69-8050-aa020afcd961" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_1c71659f-fd5f-4b74-96d2-b81c2f7c49be" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_ec30cad8-7093-4c69-8050-aa020afcd961" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CONDENSEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSS" xlink:type="simple" xlink:href="ardx-20210630.xsd#CONDENSEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSS"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CONDENSEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVELOSS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract_cef18e1a-ad1b-49d9-bcf3-cb99bab8d99a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_ec6c6e05-4a8d-4e58-ac17-85161cf9e18d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_cef18e1a-ad1b-49d9-bcf3-cb99bab8d99a" xlink:to="loc_us-gaap_StatementTable_ec6c6e05-4a8d-4e58-ac17-85161cf9e18d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_2ee7d3bb-2aa5-4609-bbb1-aac93d6e882b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_ec6c6e05-4a8d-4e58-ac17-85161cf9e18d" xlink:to="loc_srt_ProductOrServiceAxis_2ee7d3bb-2aa5-4609-bbb1-aac93d6e882b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_96dc49e9-fe1e-470f-84a9-487a5b0d257b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductOrServiceAxis_2ee7d3bb-2aa5-4609-bbb1-aac93d6e882b" xlink:to="loc_srt_ProductsAndServicesDomain_96dc49e9-fe1e-470f-84a9-487a5b0d257b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborativeDevelopmentMember_57e141d8-09f0-421d-9cfd-d44ea514f05a" xlink:href="ardx-20210630.xsd#ardx_CollaborativeDevelopmentMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductsAndServicesDomain_96dc49e9-fe1e-470f-84a9-487a5b0d257b" xlink:to="loc_ardx_CollaborativeDevelopmentMember_57e141d8-09f0-421d-9cfd-d44ea514f05a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ProductSupplyRevenueMember_511b4c53-b033-4547-ba1a-85952cb07a6e" xlink:href="ardx-20210630.xsd#ardx_ProductSupplyRevenueMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductsAndServicesDomain_96dc49e9-fe1e-470f-84a9-487a5b0d257b" xlink:to="loc_ardx_ProductSupplyRevenueMember_511b4c53-b033-4547-ba1a-85952cb07a6e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicenseMember_72b22dd5-077b-4b94-a6cf-3f0723bcf1e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LicenseMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductsAndServicesDomain_96dc49e9-fe1e-470f-84a9-487a5b0d257b" xlink:to="loc_us-gaap_LicenseMember_72b22dd5-077b-4b94-a6cf-3f0723bcf1e6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_ec6c6e05-4a8d-4e58-ac17-85161cf9e18d" xlink:to="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_db5519f4-e5f0-4cf0-b12d-2d23e06f9214" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenuesAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_RevenuesAbstract_db5519f4-e5f0-4cf0-b12d-2d23e06f9214" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_5b28498e-584a-4035-a203-0032bfe763e2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenuesAbstract_db5519f4-e5f0-4cf0-b12d-2d23e06f9214" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_5b28498e-584a-4035-a203-0032bfe763e2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_1ace8325-293f-4416-bc2b-55bee6816a7d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_OperatingExpensesAbstract_1ace8325-293f-4416-bc2b-55bee6816a7d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue_38168242-ba19-473e-afc9-b2c70ee79915" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfRevenue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ace8325-293f-4416-bc2b-55bee6816a7d" xlink:to="loc_us-gaap_CostOfRevenue_38168242-ba19-473e-afc9-b2c70ee79915" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_75ae6b60-6ffd-4066-be60-361a63d11ac9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ace8325-293f-4416-bc2b-55bee6816a7d" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_75ae6b60-6ffd-4066-be60-361a63d11ac9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_60af4401-cca0-4443-83e2-33fe103c80ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ace8325-293f-4416-bc2b-55bee6816a7d" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_60af4401-cca0-4443-83e2-33fe103c80ab" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_b9e655f9-f6a2-4f75-b60d-164b5d020895" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostsAndExpenses"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_1ace8325-293f-4416-bc2b-55bee6816a7d" xlink:to="loc_us-gaap_CostsAndExpenses_b9e655f9-f6a2-4f75-b60d-164b5d020895" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_2f1b6118-65a2-417b-9dfd-46680dc3b4d2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_OperatingIncomeLoss_2f1b6118-65a2-417b-9dfd-46680dc3b4d2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_ace43c85-eb35-4bfe-9f0b-f70f20079bc8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestExpense"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_InterestExpense_ace43c85-eb35-4bfe-9f0b-f70f20079bc8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_5f7685fb-8a50-49d0-a065-aa927a9e2e16" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_5f7685fb-8a50-49d0-a065-aa927a9e2e16" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_84cdb601-1881-47cc-b2fb-bd3aa0864ee1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_84cdb601-1881-47cc-b2fb-bd3aa0864ee1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_2a77bd9a-5ef9-4beb-bf46-bac2d1ed40b5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_2a77bd9a-5ef9-4beb-bf46-bac2d1ed40b5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_91eefbee-4b47-429c-93c0-3fc98fc64eaf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_NetIncomeLoss_91eefbee-4b47-429c-93c0-3fc98fc64eaf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_53a9ff05-52dc-4707-80f8-39acd2d21034" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_EarningsPerShareBasic_53a9ff05-52dc-4707-80f8-39acd2d21034" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_06a4aa1c-a0a5-4535-909a-83451d0bb144" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_EarningsPerShareDiluted_06a4aa1c-a0a5-4535-909a-83451d0bb144" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_bbefb560-9449-4364-97dd-34530cd790ad" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_bbefb560-9449-4364-97dd-34530cd790ad" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_40ab9e62-ec7b-42fb-a5d6-e94be3a10ada" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:presentationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_40ab9e62-ec7b-42fb-a5d6-e94be3a10ada" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_54c2e89b-f749-4573-80b4-a4ad9aaedd0f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAbstract"/>
    <link:presentationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_4db9cb01-396d-4fd0-a283-b35feb850ca6" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_54c2e89b-f749-4573-80b4-a4ad9aaedd0f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_6ac2851d-ccb9-4f71-908c-a22bb25d075f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_54c2e89b-f749-4573-80b4-a4ad9aaedd0f" xlink:to="loc_us-gaap_NetIncomeLoss_6ac2851d-ccb9-4f71-908c-a22bb25d075f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_49141fa4-a987-4e46-b4d7-d8f5bb941573" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_54c2e89b-f749-4573-80b4-a4ad9aaedd0f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_49141fa4-a987-4e46-b4d7-d8f5bb941573" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_5f09a2fb-9583-433c-a09b-a4a99b0961a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_54c2e89b-f749-4573-80b4-a4ad9aaedd0f" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_5f09a2fb-9583-433c-a09b-a4a99b0961a8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CONDENSEDSTATEMENTSOFCHANGESINSTOCKHOLDERSEQUITY" xlink:type="simple" xlink:href="ardx-20210630.xsd#CONDENSEDSTATEMENTSOFCHANGESINSTOCKHOLDERSEQUITY"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CONDENSEDSTATEMENTSOFCHANGESINSTOCKHOLDERSEQUITY" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfStockholdersEquityAbstract_5478c327-19c4-4be1-a19d-8e2f20cac05b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementOfStockholdersEquityAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_0bfd5fc5-e8c7-46db-8d23-ccbe4eddd13b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfStockholdersEquityAbstract_5478c327-19c4-4be1-a19d-8e2f20cac05b" xlink:to="loc_us-gaap_StatementTable_0bfd5fc5-e8c7-46db-8d23-ccbe4eddd13b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_4688d17e-9674-4422-835c-6dbbcd86fc18" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_0bfd5fc5-e8c7-46db-8d23-ccbe4eddd13b" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_4688d17e-9674-4422-835c-6dbbcd86fc18" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_8ea9cd57-4839-4868-8835-309b070dbb31" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_4688d17e-9674-4422-835c-6dbbcd86fc18" xlink:to="loc_us-gaap_EquityComponentDomain_8ea9cd57-4839-4868-8835-309b070dbb31" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_c24caf17-c13a-47fd-a800-610229004dd1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_8ea9cd57-4839-4868-8835-309b070dbb31" xlink:to="loc_us-gaap_CommonStockMember_c24caf17-c13a-47fd-a800-610229004dd1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_ac647f05-6221-4415-9c19-8bd7919a595e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_8ea9cd57-4839-4868-8835-309b070dbb31" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_ac647f05-6221-4415-9c19-8bd7919a595e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_3bd7392a-6781-4b0c-8189-348bfa97fa5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_8ea9cd57-4839-4868-8835-309b070dbb31" xlink:to="loc_us-gaap_RetainedEarningsMember_3bd7392a-6781-4b0c-8189-348bfa97fa5e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_3909b822-f282-44f1-ae3d-c0546c02d42f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_8ea9cd57-4839-4868-8835-309b070dbb31" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_3909b822-f282-44f1-ae3d-c0546c02d42f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_0bfd5fc5-e8c7-46db-8d23-ccbe4eddd13b" xlink:to="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_5ef49fd8-b6db-4337-a3e4-5918e6a8c071" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockholdersEquity_5ef49fd8-b6db-4337-a3e4-5918e6a8c071" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_6348810b-1c56-4e7e-af08-f1a66f56cc1d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_SharesOutstanding_6348810b-1c56-4e7e-af08-f1a66f56cc1d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_43ca3556-4968-4885-8760-7d11cfbe796d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_43ca3556-4968-4885-8760-7d11cfbe796d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_c0e8078c-18c4-4d8a-b92b-8e030c47bfea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_c0e8078c-18c4-4d8a-b92b-8e030c47bfea" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_e91ad7fa-7719-4724-a0d3-cb193985b51d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_e91ad7fa-7719-4724-a0d3-cb193985b51d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_76184be7-7b6d-4fe7-b088-eb3beff445e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_76184be7-7b6d-4fe7-b088-eb3beff445e6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_707d5b21-c5ad-4dc8-878e-60c83ea6946a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_707d5b21-c5ad-4dc8-878e-60c83ea6946a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_57af6896-377c-4428-b47e-8687d7098886" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_57af6896-377c-4428-b47e-8687d7098886" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_db8ec02b-3063-421d-8470-51a658af5d37" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_db8ec02b-3063-421d-8470-51a658af5d37" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_0432b742-336c-4f75-84a5-8b068e303865" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_0432b742-336c-4f75-84a5-8b068e303865" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_299099de-46c8-4021-9338-7d399cfe40b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_299099de-46c8-4021-9338-7d399cfe40b8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_d27dde6a-edcc-445b-b605-5a81fe326b1c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:presentationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_d27dde6a-edcc-445b-b605-5a81fe326b1c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_b07a6db2-bd73-48d1-834b-85caaaf78dcd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:presentationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_b07a6db2-bd73-48d1-834b-85caaaf78dcd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_653e01cd-e8d1-4499-b607-056ec92e8dd4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_NetIncomeLoss_653e01cd-e8d1-4499-b607-056ec92e8dd4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_7ed9e38c-8480-47f2-b0c4-50b3739e6190" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:presentationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_StockholdersEquity_7ed9e38c-8480-47f2-b0c4-50b3739e6190" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_bcf0c1b7-26c4-43cf-a0b7-e14aca2a59c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:presentationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_5680957a-7c47-4a8a-a24d-b7e79560cd7c" xlink:to="loc_us-gaap_SharesOutstanding_bcf0c1b7-26c4-43cf-a0b7-e14aca2a59c7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CONDENSEDSTATEMENTSOFCASHFLOWS" xlink:type="simple" xlink:href="ardx-20210630.xsd#CONDENSEDSTATEMENTSOFCASHFLOWS"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CONDENSEDSTATEMENTSOFCASHFLOWS" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract_aae26f18-372b-459a-9410-f225bfae0171" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1ae67d96-620a-45e9-a358-a7888fb5da8e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_aae26f18-372b-459a-9410-f225bfae0171" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1ae67d96-620a-45e9-a358-a7888fb5da8e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_12cd6492-00ab-4dfb-9f0b-13be616da786" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1ae67d96-620a-45e9-a358-a7888fb5da8e" xlink:to="loc_us-gaap_NetIncomeLoss_12cd6492-00ab-4dfb-9f0b-13be616da786" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1ae67d96-620a-45e9-a358-a7888fb5da8e" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_c5925468-8014-4d94-91b9-60a9fe845c06" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Depreciation"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:to="loc_us-gaap_Depreciation_c5925468-8014-4d94-91b9-60a9fe845c06" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_87ee97f5-c0cb-47b0-8013-21fc2f2205f6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_87ee97f5-c0cb-47b0-8013-21fc2f2205f6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfDeferredCharges_aad17ee2-4aee-4ee7-bcad-1a4e619c3a11" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AmortizationOfDeferredCharges"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:to="loc_us-gaap_AmortizationOfDeferredCharges_aad17ee2-4aee-4ee7-bcad-1a4e619c3a11" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_a02f450b-6f85-43e4-bb5f-6fd1d2f7197b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:to="loc_us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_a02f450b-6f85-43e4-bb5f-6fd1d2f7197b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense_17efc45c-60fc-44cf-8ed9-8699c183a9a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense_17efc45c-60fc-44cf-8ed9-8699c183a9a3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_3bea63fb-5e01-4eba-8456-ff69760430ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensation"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:to="loc_us-gaap_ShareBasedCompensation_3bea63fb-5e01-4eba-8456-ff69760430ba" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInDerivativeLiabilities_9edc4526-e1aa-4dbd-a701-035b4f40c83e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInDerivativeLiabilities"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:to="loc_us-gaap_IncreaseDecreaseInDerivativeLiabilities_9edc4526-e1aa-4dbd-a701-035b4f40c83e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfDebtDiscountPremium_e0da19f2-3575-4f41-908c-aa3fe9ea0655" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AmortizationOfDebtDiscountPremium"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_f71707c7-73c9-46dc-818d-f07d0c2bffbd" xlink:to="loc_us-gaap_AmortizationOfDebtDiscountPremium_e0da19f2-3575-4f41-908c-aa3fe9ea0655" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_760027b4-39f7-4243-9daa-bd6babba04f1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1ae67d96-620a-45e9-a358-a7888fb5da8e" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_760027b4-39f7-4243-9daa-bd6babba04f1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_6d9519d2-9003-45ee-93b1-e24b5b45f694" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_760027b4-39f7-4243-9daa-bd6babba04f1" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_6d9519d2-9003-45ee-93b1-e24b5b45f694" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_383f16c8-35fa-4b3c-a8da-64f39ad8d235" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_760027b4-39f7-4243-9daa-bd6babba04f1" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_383f16c8-35fa-4b3c-a8da-64f39ad8d235" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_7a00666a-18d6-462d-931d-3ca7443c8822" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_760027b4-39f7-4243-9daa-bd6babba04f1" xlink:to="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_7a00666a-18d6-462d-931d-3ca7443c8822" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_6e0ff2db-0f62-4a03-98d9-2619e395998b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_760027b4-39f7-4243-9daa-bd6babba04f1" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_6e0ff2db-0f62-4a03-98d9-2619e395998b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_db807b14-e34d-4f5d-aa16-abb2cccb2a76" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_760027b4-39f7-4243-9daa-bd6babba04f1" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_db807b14-e34d-4f5d-aa16-abb2cccb2a76" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_6599a32e-9134-413f-bad6-79eb6984fe65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_760027b4-39f7-4243-9daa-bd6babba04f1" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredRevenue_6599a32e-9134-413f-bad6-79eb6984fe65" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_894220e2-20e7-4457-9260-15fe0a88dd85" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_1ae67d96-620a-45e9-a358-a7888fb5da8e" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_894220e2-20e7-4457-9260-15fe0a88dd85" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_13075225-103e-40ca-954f-70977a8d333f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_aae26f18-372b-459a-9410-f225bfae0171" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_13075225-103e-40ca-954f-70977a8d333f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_631fba82-bc60-4d38-952c-86cbf67a79d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_13075225-103e-40ca-954f-70977a8d333f" xlink:to="loc_us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_631fba82-bc60-4d38-952c-86cbf67a79d0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireShortTermInvestments_508d9eb2-1552-4db5-8cef-123ca5149b35" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireShortTermInvestments"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_13075225-103e-40ca-954f-70977a8d333f" xlink:to="loc_us-gaap_PaymentsToAcquireShortTermInvestments_508d9eb2-1552-4db5-8cef-123ca5149b35" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_098419bc-2478-424c-aec1-cdcdef3fcbcf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_13075225-103e-40ca-954f-70977a8d333f" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_098419bc-2478-424c-aec1-cdcdef3fcbcf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_b50c7215-facb-4e44-a12c-1b89f57ee1d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_13075225-103e-40ca-954f-70977a8d333f" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_b50c7215-facb-4e44-a12c-1b89f57ee1d9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b9283af5-51eb-4d1e-9609-1fc1ee9af661" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_aae26f18-372b-459a-9410-f225bfae0171" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b9283af5-51eb-4d1e-9609-1fc1ee9af661" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_7fc3d946-ace1-499f-9344-7c99d7a64c8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b9283af5-51eb-4d1e-9609-1fc1ee9af661" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_7fc3d946-ace1-499f-9344-7c99d7a64c8b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_90aec91a-edd0-4a96-95e6-5408659f132d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b9283af5-51eb-4d1e-9609-1fc1ee9af661" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_90aec91a-edd0-4a96-95e6-5408659f132d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_54ee1918-edaa-493c-b623-5a435eafa175" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_b9283af5-51eb-4d1e-9609-1fc1ee9af661" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_54ee1918-edaa-493c-b623-5a435eafa175" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_89caa815-6284-4f8b-a398-ec871920b81b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_aae26f18-372b-459a-9410-f225bfae0171" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_89caa815-6284-4f8b-a398-ec871920b81b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_08f3bfbd-f753-47bc-827a-bb9dea72c432" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_aae26f18-372b-459a-9410-f225bfae0171" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_08f3bfbd-f753-47bc-827a-bb9dea72c432" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_282065a2-0f42-402f-8847-0f985ff4f928" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_aae26f18-372b-459a-9410-f225bfae0171" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_282065a2-0f42-402f-8847-0f985ff4f928" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_2917d61f-bc76-4b38-92ee-d8751757fe35" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_aae26f18-372b-459a-9410-f225bfae0171" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_2917d61f-bc76-4b38-92ee-d8751757fe35" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_137d5dfe-d295-486e-a99a-62fd252e5909" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InterestPaidNet"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_2917d61f-bc76-4b38-92ee-d8751757fe35" xlink:to="loc_us-gaap_InterestPaidNet_137d5dfe-d295-486e-a99a-62fd252e5909" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaidNet_d6610ece-1b5d-4734-ac30-07b5678f0d5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxesPaidNet"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_2917d61f-bc76-4b38-92ee-d8751757fe35" xlink:to="loc_us-gaap_IncomeTaxesPaidNet_d6610ece-1b5d-4734-ac30-07b5678f0d5e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_8a3b5d01-a140-4b15-b4f1-babffb0c3ddb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_aae26f18-372b-459a-9410-f225bfae0171" xlink:to="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_8a3b5d01-a140-4b15-b4f1-babffb0c3ddb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_5e661262-d2e7-4599-8c4f-3aef59ebf552" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_8a3b5d01-a140-4b15-b4f1-babffb0c3ddb" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_5e661262-d2e7-4599-8c4f-3aef59ebf552" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssued1_c62e065f-2e5b-4d7a-86ed-689fb589e11f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssued1"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_8a3b5d01-a140-4b15-b4f1-babffb0c3ddb" xlink:to="loc_us-gaap_StockIssued1_c62e065f-2e5b-4d7a-86ed-689fb589e11f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/OrganizationandBasisofPresentation" xlink:type="simple" xlink:href="ardx-20210630.xsd#OrganizationandBasisofPresentation"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/OrganizationandBasisofPresentation" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_432d81d5-877a-4d8c-892c-7441ac77fea9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock_5255bd4e-85e4-4878-ae40-8912bff07124" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_432d81d5-877a-4d8c-892c-7441ac77fea9" xlink:to="loc_us-gaap_OrganizationConsolidationBasisOfPresentationBusinessDescriptionAndAccountingPoliciesTextBlock_5255bd4e-85e4-4878-ae40-8912bff07124" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/OrganizationandBasisofPresentationPolicies" xlink:type="simple" xlink:href="ardx-20210630.xsd#OrganizationandBasisofPresentationPolicies"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/OrganizationandBasisofPresentationPolicies" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_97a37e93-e65a-413b-9762-3816891e6c4a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_1a3ce053-4968-4e3a-a4d4-789545948aef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BasisOfAccountingPolicyPolicyTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_97a37e93-e65a-413b-9762-3816891e6c4a" xlink:to="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_1a3ce053-4968-4e3a-a4d4-789545948aef" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UseOfEstimates_d31195e7-4d19-4b0a-bf30-e9d6b4e5d03d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UseOfEstimates"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_97a37e93-e65a-413b-9762-3816891e6c4a" xlink:to="loc_us-gaap_UseOfEstimates_d31195e7-4d19-4b0a-bf30-e9d6b4e5d03d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_2c86ed6d-49ae-4a85-9377-4957d607b165" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_97a37e93-e65a-413b-9762-3816891e6c4a" xlink:to="loc_us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_2c86ed6d-49ae-4a85-9377-4957d607b165" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementPolicyPolicyTextBlock_a69722a2-65bb-4291-b641-c80ba6540a20" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementPolicyPolicyTextBlock"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_97a37e93-e65a-413b-9762-3816891e6c4a" xlink:to="loc_us-gaap_FairValueMeasurementPolicyPolicyTextBlock_a69722a2-65bb-4291-b641-c80ba6540a20" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/OrganizationandBasisofPresentationDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#OrganizationandBasisofPresentationDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/OrganizationandBasisofPresentationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_ab9a7d03-0ecd-4264-9293-9ae1a26c88b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_bc5ef134-3af8-4c3d-a0c1-74e44068e989" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_ab9a7d03-0ecd-4264-9293-9ae1a26c88b8" xlink:to="loc_us-gaap_NumberOfOperatingSegments_bc5ef134-3af8-4c3d-a0c1-74e44068e989" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsAndShortTermInvestments_c1797510-53bc-4833-8269-af1004f03508" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsAndShortTermInvestments"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_ab9a7d03-0ecd-4264-9293-9ae1a26c88b8" xlink:to="loc_us-gaap_CashCashEquivalentsAndShortTermInvestments_c1797510-53bc-4833-8269-af1004f03508" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CashCashEquivalentsandInvestments" xlink:type="simple" xlink:href="ardx-20210630.xsd#CashCashEquivalentsandInvestments"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CashCashEquivalentsandInvestments" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAbstract_de5e86fa-5353-4ce3-b9b2-d6a17fc1e5d2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsAndShortTermInvestmentsTextBlock_de4dc1cd-11a6-4fd2-90b6-b25eb921c6ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashCashEquivalentsAndShortTermInvestmentsTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashAndCashEquivalentsAbstract_de5e86fa-5353-4ce3-b9b2-d6a17fc1e5d2" xlink:to="loc_us-gaap_CashCashEquivalentsAndShortTermInvestmentsTextBlock_de4dc1cd-11a6-4fd2-90b6-b25eb921c6ee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CashCashEquivalentsandInvestmentsTables" xlink:type="simple" xlink:href="ardx-20210630.xsd#CashCashEquivalentsandInvestmentsTables"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CashCashEquivalentsandInvestmentsTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAbstract_f6064d10-fee9-4c57-8b8b-728b508b5541" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashCashEquivalentsAndShortTermInvestmentsTableTextBlock_1ea393d9-adea-4eee-b735-735a0226bf8d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCashCashEquivalentsAndShortTermInvestmentsTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashAndCashEquivalentsAbstract_f6064d10-fee9-4c57-8b8b-728b508b5541" xlink:to="loc_us-gaap_ScheduleOfCashCashEquivalentsAndShortTermInvestmentsTableTextBlock_1ea393d9-adea-4eee-b735-735a0226bf8d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CashCashEquivalentsandInvestmentsSecuritiesClassifiedasCashCashEquivalentsandInvestmentsDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#CashCashEquivalentsandInvestmentsSecuritiesClassifiedasCashCashEquivalentsandInvestmentsDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CashCashEquivalentsandInvestmentsSecuritiesClassifiedasCashCashEquivalentsandInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAbstract_8a47bc29-e089-4b1a-bbba-8c148dec111e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3bf7b923-da94-4dc2-a39d-f66a280cd306" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashAndCashEquivalentsAbstract_8a47bc29-e089-4b1a-bbba-8c148dec111e" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3bf7b923-da94-4dc2-a39d-f66a280cd306" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_d101ceb7-430f-4d23-9346-1493caff86b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3bf7b923-da94-4dc2-a39d-f66a280cd306" xlink:to="loc_us-gaap_FinancialInstrumentAxis_d101ceb7-430f-4d23-9346-1493caff86b4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e758d12b-2bec-46f3-bac4-d5d4251ec6d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FinancialInstrumentAxis_d101ceb7-430f-4d23-9346-1493caff86b4" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e758d12b-2bec-46f3-bac4-d5d4251ec6d4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_ee262834-f248-4639-86b6-7d13dc9b3643" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e758d12b-2bec-46f3-bac4-d5d4251ec6d4" xlink:to="loc_us-gaap_CommercialPaperNotIncludedWithCashAndCashEquivalentsMember_ee262834-f248-4639-86b6-7d13dc9b3643" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_b2d5d545-ea94-4f6d-94bf-7dac493c8ff3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e758d12b-2bec-46f3-bac4-d5d4251ec6d4" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_b2d5d545-ea94-4f6d-94bf-7dac493c8ff3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_0df5146e-770e-41fd-becb-1fb07632b1a1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e758d12b-2bec-46f3-bac4-d5d4251ec6d4" xlink:to="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_0df5146e-770e-41fd-becb-1fb07632b1a1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_b65f77cb-cd54-4fd9-8e4b-67901c9c8886" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e758d12b-2bec-46f3-bac4-d5d4251ec6d4" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_b65f77cb-cd54-4fd9-8e4b-67901c9c8886" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryNotesSecuritiesMember_1e88da8d-b5e5-4180-8319-6088c6e04c89" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USTreasuryNotesSecuritiesMember"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e758d12b-2bec-46f3-bac4-d5d4251ec6d4" xlink:to="loc_us-gaap_USTreasuryNotesSecuritiesMember_1e88da8d-b5e5-4180-8319-6088c6e04c89" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_2fd8f682-daf6-4408-ae14-ccc3f74c22f9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3bf7b923-da94-4dc2-a39d-f66a280cd306" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_2fd8f682-daf6-4408-ae14-ccc3f74c22f9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_47e288c2-fc4d-4948-b878-99af784156ff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_2fd8f682-daf6-4408-ae14-ccc3f74c22f9" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_47e288c2-fc4d-4948-b878-99af784156ff" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashMember_b3f5ad7b-274d-499b-bbad-4ea4a9f01cda" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_47e288c2-fc4d-4948-b878-99af784156ff" xlink:to="loc_us-gaap_CashMember_b3f5ad7b-274d-499b-bbad-4ea4a9f01cda" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_7811b5cc-03d8-4dd8-9409-b7211f0af2a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_47e288c2-fc4d-4948-b878-99af784156ff" xlink:to="loc_us-gaap_MoneyMarketFundsMember_7811b5cc-03d8-4dd8-9409-b7211f0af2a7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_14e3d4cc-2466-45ee-9a7d-041b8795e7b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPaperMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_47e288c2-fc4d-4948-b878-99af784156ff" xlink:to="loc_us-gaap_CommercialPaperMember_14e3d4cc-2466-45ee-9a7d-041b8795e7b4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5b32cbce-4507-4731-9577-e35e919f53ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3bf7b923-da94-4dc2-a39d-f66a280cd306" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5b32cbce-4507-4731-9577-e35e919f53ba" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValueAbstract_26e5f0c5-db6a-494e-aa01-798da165cc95" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValueAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5b32cbce-4507-4731-9577-e35e919f53ba" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValueAbstract_26e5f0c5-db6a-494e-aa01-798da165cc95" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_e2f786e4-ae79-45d4-af14-520da6c19278" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashAndCashEquivalentsAtCarryingValueAbstract_26e5f0c5-db6a-494e-aa01-798da165cc95" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_e2f786e4-ae79-45d4-af14-520da6c19278" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_df1c1290-65f1-4b24-bcba-df9307d503bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashAndCashEquivalentsAtCarryingValueAbstract_26e5f0c5-db6a-494e-aa01-798da165cc95" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_df1c1290-65f1-4b24-bcba-df9307d503bb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_7cd0034e-f7f1-47bb-940c-711ac7128124" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5b32cbce-4507-4731-9577-e35e919f53ba" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_7cd0034e-f7f1-47bb-940c-711ac7128124" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_b20b2735-9159-4ed0-a919-ed9039116725" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_7cd0034e-f7f1-47bb-940c-711ac7128124" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_b20b2735-9159-4ed0-a919-ed9039116725" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_07088dd4-7d70-4761-a012-d6f3c030a850" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_7cd0034e-f7f1-47bb-940c-711ac7128124" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_07088dd4-7d70-4761-a012-d6f3c030a850" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_6142a82f-2217-46b3-a390-2f9f64da2bcb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_7cd0034e-f7f1-47bb-940c-711ac7128124" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_6142a82f-2217-46b3-a390-2f9f64da2bcb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_34facfde-5ae1-44e3-9d7b-4a00d84072ea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AvailableForSaleSecuritiesFairValueToAmortizedCostBasisAbstract_7cd0034e-f7f1-47bb-940c-711ac7128124" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_34facfde-5ae1-44e3-9d7b-4a00d84072ea" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermInvestmentsAbstract_d13d5ff9-e955-4e8c-b533-1c8103b12a8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermInvestmentsAbstract"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5b32cbce-4507-4731-9577-e35e919f53ba" xlink:to="loc_us-gaap_LongTermInvestmentsAbstract_d13d5ff9-e955-4e8c-b533-1c8103b12a8b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LongTermInvestmentsAmortizedCost_91648fbd-2768-4e0c-b01c-0fda46cb78e4" xlink:href="ardx-20210630.xsd#ardx_LongTermInvestmentsAmortizedCost"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermInvestmentsAbstract_d13d5ff9-e955-4e8c-b533-1c8103b12a8b" xlink:to="loc_ardx_LongTermInvestmentsAmortizedCost_91648fbd-2768-4e0c-b01c-0fda46cb78e4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LongTermInvestmentsAccumulatedGrossUnrealizedGain_10306606-9a9e-4a91-a3d6-fb5c2372b0a9" xlink:href="ardx-20210630.xsd#ardx_LongTermInvestmentsAccumulatedGrossUnrealizedGain"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermInvestmentsAbstract_d13d5ff9-e955-4e8c-b533-1c8103b12a8b" xlink:to="loc_ardx_LongTermInvestmentsAccumulatedGrossUnrealizedGain_10306606-9a9e-4a91-a3d6-fb5c2372b0a9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LongTermInvestmentsAccumulatedGrossUnrealizedLoss_2ffd1f2f-b3e1-4e86-aea9-5ef066cdfa79" xlink:href="ardx-20210630.xsd#ardx_LongTermInvestmentsAccumulatedGrossUnrealizedLoss"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermInvestmentsAbstract_d13d5ff9-e955-4e8c-b533-1c8103b12a8b" xlink:to="loc_ardx_LongTermInvestmentsAccumulatedGrossUnrealizedLoss_2ffd1f2f-b3e1-4e86-aea9-5ef066cdfa79" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LongTermInvestmentsFairValue_5aaacc93-4b52-46c6-834e-6e204bf2f75a" xlink:href="ardx-20210630.xsd#ardx_LongTermInvestmentsFairValue"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermInvestmentsAbstract_d13d5ff9-e955-4e8c-b533-1c8103b12a8b" xlink:to="loc_ardx_LongTermInvestmentsFairValue_5aaacc93-4b52-46c6-834e-6e204bf2f75a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsAndCash_901a5aa0-4915-49ad-99db-4a9f3ddfd36d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentsAndCash"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5b32cbce-4507-4731-9577-e35e919f53ba" xlink:to="loc_us-gaap_InvestmentsAndCash_901a5aa0-4915-49ad-99db-4a9f3ddfd36d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_InvestmentsAndCashAccumulatedGrossUnrealizedGain_79d6c5d2-94fa-408b-aa3a-69a558bf7626" xlink:href="ardx-20210630.xsd#ardx_InvestmentsAndCashAccumulatedGrossUnrealizedGain"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5b32cbce-4507-4731-9577-e35e919f53ba" xlink:to="loc_ardx_InvestmentsAndCashAccumulatedGrossUnrealizedGain_79d6c5d2-94fa-408b-aa3a-69a558bf7626" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_InvestmentsAndCashAccumulatedGrossUnrealizedLoss_01716b77-c63f-4817-919a-63aeebef2aa1" xlink:href="ardx-20210630.xsd#ardx_InvestmentsAndCashAccumulatedGrossUnrealizedLoss"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5b32cbce-4507-4731-9577-e35e919f53ba" xlink:to="loc_ardx_InvestmentsAndCashAccumulatedGrossUnrealizedLoss_01716b77-c63f-4817-919a-63aeebef2aa1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_InvestmentsAndCashFairValueDisclosure_dbe13399-ae93-43a0-b45d-a4f701f1bc2b" xlink:href="ardx-20210630.xsd#ardx_InvestmentsAndCashFairValueDisclosure"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_5b32cbce-4507-4731-9577-e35e919f53ba" xlink:to="loc_ardx_InvestmentsAndCashFairValueDisclosure_dbe13399-ae93-43a0-b45d-a4f701f1bc2b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CashCashEquivalentsandInvestmentsNarrativeDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#CashCashEquivalentsandInvestmentsNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CashCashEquivalentsandInvestmentsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAbstract_6d15685d-2428-4ce4-9335-8de9c8c7f206" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashAndCashEquivalentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSale_967f52fc-0642-4862-ae59-bba2a3cdf70e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSale"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashAndCashEquivalentsAbstract_6d15685d-2428-4ce4-9335-8de9c8c7f206" xlink:to="loc_us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSale_967f52fc-0642-4862-ae59-bba2a3cdf70e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_933cb4cf-87f6-4b87-83f2-1d7d756233fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashAndCashEquivalentsAbstract_6d15685d-2428-4ce4-9335-8de9c8c7f206" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_933cb4cf-87f6-4b87-83f2-1d7d756233fe" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/FairValueMeasurements" xlink:type="simple" xlink:href="ardx-20210630.xsd#FairValueMeasurements"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/FairValueMeasurements" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract_5ae6c08f-472d-4dc3-a3fe-150c06ce03dd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresTextBlock_aee50621-d945-4a86-9f21-99073602eaa9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosuresTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract_5ae6c08f-472d-4dc3-a3fe-150c06ce03dd" xlink:to="loc_us-gaap_FairValueDisclosuresTextBlock_aee50621-d945-4a86-9f21-99073602eaa9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/FairValueMeasurementsTables" xlink:type="simple" xlink:href="ardx-20210630.xsd#FairValueMeasurementsTables"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/FairValueMeasurementsTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract_5e5f23ec-6d4d-4dc8-8cdb-ca091c69c760" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_632e2b5e-e562-4e51-9678-6dc4833b2e4a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract_5e5f23ec-6d4d-4dc8-8cdb-ca091c69c760" xlink:to="loc_us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock_632e2b5e-e562-4e51-9678-6dc4833b2e4a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/FairValueMeasurementsDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#FairValueMeasurementsDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/FairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract_ba7a4dd5-0600-4ddb-bba1-e6ba03e454c5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3de2bb8e-91ff-4426-9c8b-00edaeb2ed60" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract_ba7a4dd5-0600-4ddb-bba1-e6ba03e454c5" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3de2bb8e-91ff-4426-9c8b-00edaeb2ed60" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_4b694da9-56cb-489b-96f9-e028a6bbf445" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3de2bb8e-91ff-4426-9c8b-00edaeb2ed60" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_4b694da9-56cb-489b-96f9-e028a6bbf445" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_0e250ed7-13b9-494e-8e40-4ffd7e0665c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_4b694da9-56cb-489b-96f9-e028a6bbf445" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_0e250ed7-13b9-494e-8e40-4ffd7e0665c9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_33455a0b-ac3c-4617-9495-9b198408c94a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_0e250ed7-13b9-494e-8e40-4ffd7e0665c9" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_33455a0b-ac3c-4617-9495-9b198408c94a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_f090ade5-19f4-4867-999f-406cb33a8746" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3de2bb8e-91ff-4426-9c8b-00edaeb2ed60" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_f090ade5-19f4-4867-999f-406cb33a8746" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d06c786c-a70d-498e-a129-08fa4347975c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_f090ade5-19f4-4867-999f-406cb33a8746" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d06c786c-a70d-498e-a129-08fa4347975c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_3c9980eb-a578-4554-981b-d23d2aa5b83c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d06c786c-a70d-498e-a129-08fa4347975c" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_3c9980eb-a578-4554-981b-d23d2aa5b83c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_873b7c9d-f5d3-4724-bb86-1c709df8c6ec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d06c786c-a70d-498e-a129-08fa4347975c" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_873b7c9d-f5d3-4724-bb86-1c709df8c6ec" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_9c838c75-3d02-4cd3-9f50-8848bf42ac9c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d06c786c-a70d-498e-a129-08fa4347975c" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_9c838c75-3d02-4cd3-9f50-8848bf42ac9c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_d7f8b1b9-41b3-490d-adb0-e8efeca5be13" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3de2bb8e-91ff-4426-9c8b-00edaeb2ed60" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_d7f8b1b9-41b3-490d-adb0-e8efeca5be13" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_893b1935-d928-4e87-bb10-94aa2690dba7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_d7f8b1b9-41b3-490d-adb0-e8efeca5be13" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_893b1935-d928-4e87-bb10-94aa2690dba7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_d0a3837d-c5f1-421f-932e-8907cad3ec93" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_893b1935-d928-4e87-bb10-94aa2690dba7" xlink:to="loc_us-gaap_MoneyMarketFundsMember_d0a3837d-c5f1-421f-932e-8907cad3ec93" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_0296e6c6-e0f8-4d4e-816f-5a3a3beb739c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommercialPaperMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_893b1935-d928-4e87-bb10-94aa2690dba7" xlink:to="loc_us-gaap_CommercialPaperMember_0296e6c6-e0f8-4d4e-816f-5a3a3beb739c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_c23de353-289d-431b-bc1f-4ee5d9c214ec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_893b1935-d928-4e87-bb10-94aa2690dba7" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_c23de353-289d-431b-bc1f-4ee5d9c214ec" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_7fb4c03f-06cf-4f9a-a759-af0fa48cff16" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_893b1935-d928-4e87-bb10-94aa2690dba7" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_7fb4c03f-06cf-4f9a-a759-af0fa48cff16" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_2cd03617-3cd1-4a5d-8819-46bfcbea79fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_893b1935-d928-4e87-bb10-94aa2690dba7" xlink:to="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_2cd03617-3cd1-4a5d-8819-46bfcbea79fe" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryNotesSecuritiesMember_ed3a311f-7bfe-44cc-b7a6-913d6e9766e8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USTreasuryNotesSecuritiesMember"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_893b1935-d928-4e87-bb10-94aa2690dba7" xlink:to="loc_us-gaap_USTreasuryNotesSecuritiesMember_ed3a311f-7bfe-44cc-b7a6-913d6e9766e8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_e7afa2fc-99eb-41ee-af8d-7ee73cffe992" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3de2bb8e-91ff-4426-9c8b-00edaeb2ed60" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_e7afa2fc-99eb-41ee-af8d-7ee73cffe992" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_2eadd0b7-78b7-47d6-b271-db041ea28d17" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_e7afa2fc-99eb-41ee-af8d-7ee73cffe992" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_2eadd0b7-78b7-47d6-b271-db041ea28d17" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember_dc4bea7f-47d1-4156-adc6-0bdc2cd67375" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_2eadd0b7-78b7-47d6-b271-db041ea28d17" xlink:to="loc_us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember_dc4bea7f-47d1-4156-adc6-0bdc2cd67375" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_c875994f-1c8c-45b2-b6f2-e67b497f1af9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_3de2bb8e-91ff-4426-9c8b-00edaeb2ed60" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_c875994f-1c8c-45b2-b6f2-e67b497f1af9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_3659c434-a0ab-4593-8939-873ca0c18bdf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_c875994f-1c8c-45b2-b6f2-e67b497f1af9" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_3659c434-a0ab-4593-8939-873ca0c18bdf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_1cb03204-c366-4989-8d7e-72bf03c119cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_3659c434-a0ab-4593-8939-873ca0c18bdf" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_1cb03204-c366-4989-8d7e-72bf03c119cf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_e55cacf0-38c4-4703-b158-cd45812b13af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_c875994f-1c8c-45b2-b6f2-e67b497f1af9" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_e55cacf0-38c4-4703-b158-cd45812b13af" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_ebb0024a-c3ca-4516-b968-831f5cf1af1a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_e55cacf0-38c4-4703-b158-cd45812b13af" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_ebb0024a-c3ca-4516-b968-831f5cf1af1a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CollaborationandLicensingAgreements" xlink:type="simple" xlink:href="ardx-20210630.xsd#CollaborationandLicensingAgreements"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CollaborationandLicensingAgreements" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborationAndLicensingAgreementsAbstract_c85dc9a2-b2d4-4e9f-9e53-a51648067b5a" xlink:href="ardx-20210630.xsd#ardx_CollaborationAndLicensingAgreementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementDisclosureTextBlock_f73be9d3-46e1-4873-ab08-44e8385799d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollaborativeArrangementDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_CollaborationAndLicensingAgreementsAbstract_c85dc9a2-b2d4-4e9f-9e53-a51648067b5a" xlink:to="loc_us-gaap_CollaborativeArrangementDisclosureTextBlock_f73be9d3-46e1-4873-ab08-44e8385799d9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CollaborationandLicensingAgreementsTables" xlink:type="simple" xlink:href="ardx-20210630.xsd#CollaborationandLicensingAgreementsTables"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CollaborationandLicensingAgreementsTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborationAndLicensingAgreementsAbstract_78edfaef-7097-4557-8c6c-77542d290397" xlink:href="ardx-20210630.xsd#ardx_CollaborationAndLicensingAgreementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock_b720bf55-8218-40eb-ab0c-ce4f7c49bcb7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_CollaborationAndLicensingAgreementsAbstract_78edfaef-7097-4557-8c6c-77542d290397" xlink:to="loc_us-gaap_ContractWithCustomerAssetAndLiabilityTableTextBlock_b720bf55-8218-40eb-ab0c-ce4f7c49bcb7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CollaborationandLicensingAgreementsNarrativeDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#CollaborationandLicensingAgreementsNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CollaborationandLicensingAgreementsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborationAndLicensingAgreementsAbstract_1921b9ab-8392-4fd2-aa2d-b4aef469ceb7" xlink:href="ardx-20210630.xsd#ardx_CollaborationAndLicensingAgreementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_65d21f3d-ba78-47f8-a0db-2f81a0cb43a6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_CollaborationAndLicensingAgreementsAbstract_1921b9ab-8392-4fd2-aa2d-b4aef469ceb7" xlink:to="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_65d21f3d-ba78-47f8-a0db-2f81a0cb43a6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_cdc23faf-653b-4dc4-aa57-221c3c83b40f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_65d21f3d-ba78-47f8-a0db-2f81a0cb43a6" xlink:to="loc_us-gaap_TypeOfArrangementAxis_cdc23faf-653b-4dc4-aa57-221c3c83b40f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_fa502ced-42d3-44cb-b029-82b63bfc5f8f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TypeOfArrangementAxis_cdc23faf-653b-4dc4-aa57-221c3c83b40f" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_fa502ced-42d3-44cb-b029-82b63bfc5f8f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ResearchCollaborationAndOptionAgreementMember_29f911c1-93ba-4778-a596-bb49c6427564" xlink:href="ardx-20210630.xsd#ardx_ResearchCollaborationAndOptionAgreementMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_fa502ced-42d3-44cb-b029-82b63bfc5f8f" xlink:to="loc_ardx_ResearchCollaborationAndOptionAgreementMember_29f911c1-93ba-4778-a596-bb49c6427564" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LicenseAgreementDevelopmentCommercializationDistributionInJapanMember_bfff45a0-8216-453a-95ef-1a63f59fa878" xlink:href="ardx-20210630.xsd#ardx_LicenseAgreementDevelopmentCommercializationDistributionInJapanMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_fa502ced-42d3-44cb-b029-82b63bfc5f8f" xlink:to="loc_ardx_LicenseAgreementDevelopmentCommercializationDistributionInJapanMember_bfff45a0-8216-453a-95ef-1a63f59fa878" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LicenseAgreementDevelopmentCommercializationDistributionInChinaMember_4cc4b53d-bc6c-4019-bf3d-501abc436a36" xlink:href="ardx-20210630.xsd#ardx_LicenseAgreementDevelopmentCommercializationDistributionInChinaMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_fa502ced-42d3-44cb-b029-82b63bfc5f8f" xlink:to="loc_ardx_LicenseAgreementDevelopmentCommercializationDistributionInChinaMember_4cc4b53d-bc6c-4019-bf3d-501abc436a36" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LicenseAgreementDevelopmentCommercializationDistributionInCanadaMember_77c8f4bd-d6aa-4f1f-9fd0-ce6ab4202e4b" xlink:href="ardx-20210630.xsd#ardx_LicenseAgreementDevelopmentCommercializationDistributionInCanadaMember"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_fa502ced-42d3-44cb-b029-82b63bfc5f8f" xlink:to="loc_ardx_LicenseAgreementDevelopmentCommercializationDistributionInCanadaMember_77c8f4bd-d6aa-4f1f-9fd0-ce6ab4202e4b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_AstraZenecaTerminationAgreementMember_8cb148b8-1dc5-409d-8d4b-3624e82b1751" xlink:href="ardx-20210630.xsd#ardx_AstraZenecaTerminationAgreementMember"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_fa502ced-42d3-44cb-b029-82b63bfc5f8f" xlink:to="loc_ardx_AstraZenecaTerminationAgreementMember_8cb148b8-1dc5-409d-8d4b-3624e82b1751" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_0f33ab83-9a13-4f03-b9dc-516aaf2fa14c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CounterpartyNameAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_65d21f3d-ba78-47f8-a0db-2f81a0cb43a6" xlink:to="loc_srt_CounterpartyNameAxis_0f33ab83-9a13-4f03-b9dc-516aaf2fa14c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58e89a81-e2b9-4bfd-991a-9329ee42da05" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_CounterpartyNameAxis_0f33ab83-9a13-4f03-b9dc-516aaf2fa14c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58e89a81-e2b9-4bfd-991a-9329ee42da05" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_KyowaKirinCo.LtdMember_eeb5ef01-7863-4ea8-b3a4-84aa1bf68c94" xlink:href="ardx-20210630.xsd#ardx_KyowaKirinCo.LtdMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58e89a81-e2b9-4bfd-991a-9329ee42da05" xlink:to="loc_ardx_KyowaKirinCo.LtdMember_eeb5ef01-7863-4ea8-b3a4-84aa1bf68c94" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ShanghaiFosunPharmaceuticalIndustrialDevelopmentMember_82741568-0f60-44a4-a042-c6e08a54dcc7" xlink:href="ardx-20210630.xsd#ardx_ShanghaiFosunPharmaceuticalIndustrialDevelopmentMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58e89a81-e2b9-4bfd-991a-9329ee42da05" xlink:to="loc_ardx_ShanghaiFosunPharmaceuticalIndustrialDevelopmentMember_82741568-0f60-44a4-a042-c6e08a54dcc7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_KnightTherapeuticsIncMember_7d67c4d4-ed17-4fcb-afaf-621df77f1f4c" xlink:href="ardx-20210630.xsd#ardx_KnightTherapeuticsIncMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58e89a81-e2b9-4bfd-991a-9329ee42da05" xlink:to="loc_ardx_KnightTherapeuticsIncMember_7d67c4d4-ed17-4fcb-afaf-621df77f1f4c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_AstrazenecaMember_3f2b1b36-aeb4-4d16-9ff2-65fd0a42a66b" xlink:href="ardx-20210630.xsd#ardx_AstrazenecaMember"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_58e89a81-e2b9-4bfd-991a-9329ee42da05" xlink:to="loc_ardx_AstrazenecaMember_3f2b1b36-aeb4-4d16-9ff2-65fd0a42a66b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_34883593-b176-49a3-b83d-765bb2c45092" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_65d21f3d-ba78-47f8-a0db-2f81a0cb43a6" xlink:to="loc_srt_ProductOrServiceAxis_34883593-b176-49a3-b83d-765bb2c45092" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_0fd80c17-2639-4f86-a180-4c0d618f0928" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductOrServiceAxis_34883593-b176-49a3-b83d-765bb2c45092" xlink:to="loc_srt_ProductsAndServicesDomain_0fd80c17-2639-4f86-a180-4c0d618f0928" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicenseMember_27f40f9d-243e-4cbf-a5e1-92b8948c636f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LicenseMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductsAndServicesDomain_0fd80c17-2639-4f86-a180-4c0d618f0928" xlink:to="loc_us-gaap_LicenseMember_27f40f9d-243e-4cbf-a5e1-92b8948c636f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ProductSupplyRevenueMember_89345957-7227-4713-821f-9dac832356ea" xlink:href="ardx-20210630.xsd#ardx_ProductSupplyRevenueMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductsAndServicesDomain_0fd80c17-2639-4f86-a180-4c0d618f0928" xlink:to="loc_ardx_ProductSupplyRevenueMember_89345957-7227-4713-821f-9dac832356ea" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_OtherProductOrServicesRevenueMember_f6cffe0a-7109-4d30-b254-cf675b661a09" xlink:href="ardx-20210630.xsd#ardx_OtherProductOrServicesRevenueMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductsAndServicesDomain_0fd80c17-2639-4f86-a180-4c0d618f0928" xlink:to="loc_ardx_OtherProductOrServicesRevenueMember_f6cffe0a-7109-4d30-b254-cf675b661a09" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_ad46c20a-be3e-4f17-ad43-563f46b91d13" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_65d21f3d-ba78-47f8-a0db-2f81a0cb43a6" xlink:to="loc_srt_RangeAxis_ad46c20a-be3e-4f17-ad43-563f46b91d13" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_d6bbf08d-c84f-44ee-aaf2-0a12d4727485" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeAxis_ad46c20a-be3e-4f17-ad43-563f46b91d13" xlink:to="loc_srt_RangeMember_d6bbf08d-c84f-44ee-aaf2-0a12d4727485" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_7bec31b9-54c0-4829-968c-c4cedc63be3f" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_d6bbf08d-c84f-44ee-aaf2-0a12d4727485" xlink:to="loc_srt_MinimumMember_7bec31b9-54c0-4829-968c-c4cedc63be3f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_65d21f3d-ba78-47f8-a0db-2f81a0cb43a6" xlink:to="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_NumberOfSeparateCollaborativeAgreements_f54d7fa1-9665-4e6a-aa5c-1d7f6a116d02" xlink:href="ardx-20210630.xsd#ardx_NumberOfSeparateCollaborativeAgreements"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_NumberOfSeparateCollaborativeAgreements_f54d7fa1-9665-4e6a-aa5c-1d7f6a116d02" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborationAndLicensingAgreementsUpfrontLicenseFees_df12f52c-f16f-499d-9c92-98a9096b6e57" xlink:href="ardx-20210630.xsd#ardx_CollaborationAndLicensingAgreementsUpfrontLicenseFees"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_CollaborationAndLicensingAgreementsUpfrontLicenseFees_df12f52c-f16f-499d-9c92-98a9096b6e57" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborationAndLicensingAgreementsUpfrontLicenseFeesFirstInstallment_4fac8d96-d633-432c-aa83-acab63fb9aed" xlink:href="ardx-20210630.xsd#ardx_CollaborationAndLicensingAgreementsUpfrontLicenseFeesFirstInstallment"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_CollaborationAndLicensingAgreementsUpfrontLicenseFeesFirstInstallment_4fac8d96-d633-432c-aa83-acab63fb9aed" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_TermOfPaymentOfLicenseFeeFirstInstallment_8b11504e-89ab-41ce-9553-e81fbfe479c7" xlink:href="ardx-20210630.xsd#ardx_TermOfPaymentOfLicenseFeeFirstInstallment"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_TermOfPaymentOfLicenseFeeFirstInstallment_8b11504e-89ab-41ce-9553-e81fbfe479c7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborationAndLicensingAgreementsUpfrontLicenseFeesSecondInstallment_a195c334-3e3c-4210-aa31-1d5798318871" xlink:href="ardx-20210630.xsd#ardx_CollaborationAndLicensingAgreementsUpfrontLicenseFeesSecondInstallment"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_CollaborationAndLicensingAgreementsUpfrontLicenseFeesSecondInstallment_a195c334-3e3c-4210-aa31-1d5798318871" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_TermOfAgreement_b8f067af-fae3-4924-94b0-f057ca34f4df" xlink:href="ardx-20210630.xsd#ardx_TermOfAgreement"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_TermOfAgreement_b8f067af-fae3-4924-94b0-f057ca34f4df" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ContractWithCustomerLiabilityRevenueRecognizedCashReceived_49945e46-f26f-498b-8c04-e4f9f5dcd7a3" xlink:href="ardx-20210630.xsd#ardx_ContractWithCustomerLiabilityRevenueRecognizedCashReceived"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_ContractWithCustomerLiabilityRevenueRecognizedCashReceived_49945e46-f26f-498b-8c04-e4f9f5dcd7a3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_1e2aefa6-33e8-4fec-b985-5a73e2620808" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_1e2aefa6-33e8-4fec-b985-5a73e2620808" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborativeArrangementPotentialDevelopmentMilestones_cbc4ed5e-a681-403d-bdc7-17ede1a143dd" xlink:href="ardx-20210630.xsd#ardx_CollaborativeArrangementPotentialDevelopmentMilestones"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_CollaborativeArrangementPotentialDevelopmentMilestones_cbc4ed5e-a681-403d-bdc7-17ede1a143dd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_eccf0564-9c3c-4ecf-8486-8e053539ccd1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_eccf0564-9c3c-4ecf-8486-8e053539ccd1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborativeArrangementPotentialCommercializationMilestones_ac99689d-50be-4c1d-88e3-b57e51be341c" xlink:href="ardx-20210630.xsd#ardx_CollaborativeArrangementPotentialCommercializationMilestones"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_CollaborativeArrangementPotentialCommercializationMilestones_ac99689d-50be-4c1d-88e3-b57e51be341c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ContractWithCustomerLiabilityIncreaseForAmountsInvoiced_56d23ae1-cd9e-4e21-9aaf-d4776ab09e17" xlink:href="ardx-20210630.xsd#ardx_ContractWithCustomerLiabilityIncreaseForAmountsInvoiced"/>
    <link:presentationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_ContractWithCustomerLiabilityIncreaseForAmountsInvoiced_56d23ae1-cd9e-4e21-9aaf-d4776ab09e17" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromLicenseFeesReceived_b22c669b-348f-4ce3-bd7e-24b60ea115e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromLicenseFeesReceived"/>
    <link:presentationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_us-gaap_ProceedsFromLicenseFeesReceived_b22c669b-348f-4ce3-bd7e-24b60ea115e1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborativeArrangementPotentialDevelopmentAndCommercializationMilestones_9b388547-b813-4c34-b1ab-4b4ba41e53b3" xlink:href="ardx-20210630.xsd#ardx_CollaborativeArrangementPotentialDevelopmentAndCommercializationMilestones"/>
    <link:presentationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_CollaborativeArrangementPotentialDevelopmentAndCommercializationMilestones_9b388547-b813-4c34-b1ab-4b4ba41e53b3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ThresholdPercentageOfSalesForTieredRoyalties_8f1b46e4-a5ca-41b8-a9f4-3f779e82e8a4" xlink:href="ardx-20210630.xsd#ardx_ThresholdPercentageOfSalesForTieredRoyalties"/>
    <link:presentationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_ThresholdPercentageOfSalesForTieredRoyalties_8f1b46e4-a5ca-41b8-a9f4-3f779e82e8a4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_PercentageOfRoyaltyRevenue_76671de8-17db-4456-9621-32814f1b48eb" xlink:href="ardx-20210630.xsd#ardx_PercentageOfRoyaltyRevenue"/>
    <link:presentationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_PercentageOfRoyaltyRevenue_76671de8-17db-4456-9621-32814f1b48eb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_PercentageOfNonRoyaltyRevenue_26c97db8-22c3-43ec-a64e-44873d0c6c1f" xlink:href="ardx-20210630.xsd#ardx_PercentageOfNonRoyaltyRevenue"/>
    <link:presentationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_PercentageOfNonRoyaltyRevenue_26c97db8-22c3-43ec-a64e-44873d0c6c1f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborativeArrangementPotentialPaymentPerTerminationAgreementMaximum_c4a3842a-c7bd-42fe-9e18-8e7e8c1e8d5d" xlink:href="ardx-20210630.xsd#ardx_CollaborativeArrangementPotentialPaymentPerTerminationAgreementMaximum"/>
    <link:presentationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_CollaborativeArrangementPotentialPaymentPerTerminationAgreementMaximum_c4a3842a-c7bd-42fe-9e18-8e7e8c1e8d5d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue_9736586b-3f98-4443-b677-916c160b2611" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfRevenue"/>
    <link:presentationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_us-gaap_CostOfRevenue_9736586b-3f98-4443-b677-916c160b2611" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_PaymentsOfUnchargedLicenseFees_fd06c4a2-c449-4428-bef3-9138846e9481" xlink:href="ardx-20210630.xsd#ardx_PaymentsOfUnchargedLicenseFees"/>
    <link:presentationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_88b687f4-0b16-4c72-ada3-6dffb663213a" xlink:to="loc_ardx_PaymentsOfUnchargedLicenseFees_fd06c4a2-c449-4428-bef3-9138846e9481" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/CollaborationandLicensingAgreementsDeferredRevenueDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#CollaborationandLicensingAgreementsDeferredRevenueDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/CollaborationandLicensingAgreementsDeferredRevenueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ardx_CollaborationAndLicensingAgreementsAbstract_b36ac5cc-5d9c-4ffb-8b7e-f93d4577fe87" xlink:href="ardx-20210630.xsd#ardx_CollaborationAndLicensingAgreementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_f4d9d08e-b454-418e-97d1-81a9f392f474" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_CollaborationAndLicensingAgreementsAbstract_b36ac5cc-5d9c-4ffb-8b7e-f93d4577fe87" xlink:to="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_f4d9d08e-b454-418e-97d1-81a9f392f474" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_76c33591-9d97-41b1-b47c-848b9022fecd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_f4d9d08e-b454-418e-97d1-81a9f392f474" xlink:to="loc_us-gaap_TypeOfArrangementAxis_76c33591-9d97-41b1-b47c-848b9022fecd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_35304241-0186-4c14-806c-d36021e7a048" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TypeOfArrangementAxis_76c33591-9d97-41b1-b47c-848b9022fecd" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_35304241-0186-4c14-806c-d36021e7a048" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ResearchCollaborationAndOptionAgreementMember_6edee05e-ce85-46fc-8f59-899887f0ebaf" xlink:href="ardx-20210630.xsd#ardx_ResearchCollaborationAndOptionAgreementMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_35304241-0186-4c14-806c-d36021e7a048" xlink:to="loc_ardx_ResearchCollaborationAndOptionAgreementMember_6edee05e-ce85-46fc-8f59-899887f0ebaf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LicenseAgreementDevelopmentCommercializationDistributionInJapanMember_b7025736-f60a-42d6-a19d-b3b743d5a608" xlink:href="ardx-20210630.xsd#ardx_LicenseAgreementDevelopmentCommercializationDistributionInJapanMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_35304241-0186-4c14-806c-d36021e7a048" xlink:to="loc_ardx_LicenseAgreementDevelopmentCommercializationDistributionInJapanMember_b7025736-f60a-42d6-a19d-b3b743d5a608" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6a8fca85-d723-4cf6-a748-146ac032acba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_f4d9d08e-b454-418e-97d1-81a9f392f474" xlink:to="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6a8fca85-d723-4cf6-a748-146ac032acba" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ChangeInContractWithCustomerLiabilityCurrentRollforwardRollForward_cc0d00ef-196c-4add-aca7-968e061cf27a" xlink:href="ardx-20210630.xsd#ardx_ChangeInContractWithCustomerLiabilityCurrentRollforwardRollForward"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6a8fca85-d723-4cf6-a748-146ac032acba" xlink:to="loc_ardx_ChangeInContractWithCustomerLiabilityCurrentRollforwardRollForward_cc0d00ef-196c-4add-aca7-968e061cf27a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_d2805ec7-b19c-4812-b825-4fa80fdd9835" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_ChangeInContractWithCustomerLiabilityCurrentRollforwardRollForward_cc0d00ef-196c-4add-aca7-968e061cf27a" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_d2805ec7-b19c-4812-b825-4fa80fdd9835" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ContractWithCustomerLiabilityRevenueRecognizedCashReceived_360c6f52-02e3-4845-b369-f3bcbc88a6fb" xlink:href="ardx-20210630.xsd#ardx_ContractWithCustomerLiabilityRevenueRecognizedCashReceived"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_ChangeInContractWithCustomerLiabilityCurrentRollforwardRollForward_cc0d00ef-196c-4add-aca7-968e061cf27a" xlink:to="loc_ardx_ContractWithCustomerLiabilityRevenueRecognizedCashReceived_360c6f52-02e3-4845-b369-f3bcbc88a6fb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_ca3eb690-ae76-454b-a4ae-ca4b4cdb80cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_ChangeInContractWithCustomerLiabilityCurrentRollforwardRollForward_cc0d00ef-196c-4add-aca7-968e061cf27a" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_ca3eb690-ae76-454b-a4ae-ca4b4cdb80cf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ChangeInContractWithCustomerLiabilityNoncurrentRollforwardRollForward_29bf1717-09c7-4b08-9fe6-5839034b3db6" xlink:href="ardx-20210630.xsd#ardx_ChangeInContractWithCustomerLiabilityNoncurrentRollforwardRollForward"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_6a8fca85-d723-4cf6-a748-146ac032acba" xlink:to="loc_ardx_ChangeInContractWithCustomerLiabilityNoncurrentRollforwardRollForward_29bf1717-09c7-4b08-9fe6-5839034b3db6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_026d9fbf-bf02-4df6-a3bc-14b29cfd87cd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_ChangeInContractWithCustomerLiabilityNoncurrentRollforwardRollForward_29bf1717-09c7-4b08-9fe6-5839034b3db6" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_026d9fbf-bf02-4df6-a3bc-14b29cfd87cd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ContractWithCustomerLiabilityIncreaseForAmountsInvoiced_ab1a28a4-399a-47ed-9be1-94cdcff3bf2a" xlink:href="ardx-20210630.xsd#ardx_ContractWithCustomerLiabilityIncreaseForAmountsInvoiced"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_ChangeInContractWithCustomerLiabilityNoncurrentRollforwardRollForward_29bf1717-09c7-4b08-9fe6-5839034b3db6" xlink:to="loc_ardx_ContractWithCustomerLiabilityIncreaseForAmountsInvoiced_ab1a28a4-399a-47ed-9be1-94cdcff3bf2a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_4c1ce90b-6309-4fc5-a602-25462ac8aafe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_ChangeInContractWithCustomerLiabilityNoncurrentRollforwardRollForward_29bf1717-09c7-4b08-9fe6-5839034b3db6" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_4c1ce90b-6309-4fc5-a602-25462ac8aafe" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/Borrowing" xlink:type="simple" xlink:href="ardx-20210630.xsd#Borrowing"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/Borrowing" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract_d19fcdb9-2008-45d9-b34a-7208c2d9c15c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureTextBlock_503f8c9c-4948-4cc3-9e95-790505cffa76" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_d19fcdb9-2008-45d9-b34a-7208c2d9c15c" xlink:to="loc_us-gaap_DebtDisclosureTextBlock_503f8c9c-4948-4cc3-9e95-790505cffa76" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/BorrowingTables" xlink:type="simple" xlink:href="ardx-20210630.xsd#BorrowingTables"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/BorrowingTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract_3f7e76b8-e768-4cf6-b6f5-cce00b5dd367" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_365dfa09-64b7-49aa-8c9f-b2e21c2c65a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_3f7e76b8-e768-4cf6-b6f5-cce00b5dd367" xlink:to="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_365dfa09-64b7-49aa-8c9f-b2e21c2c65a3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/BorrowingNarrativeDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#BorrowingNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/BorrowingNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract_2f370e01-1f37-461b-bdac-25b7a733ef57" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_98e62e15-304e-4885-b31a-5d4dd90e3e83" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_2f370e01-1f37-461b-bdac-25b7a733ef57" xlink:to="loc_us-gaap_DebtInstrumentTable_98e62e15-304e-4885-b31a-5d4dd90e3e83" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_05d4c069-6b39-4ab3-9fd0-c2d7bac60c0a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentTable_98e62e15-304e-4885-b31a-5d4dd90e3e83" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_05d4c069-6b39-4ab3-9fd0-c2d7bac60c0a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_f8ab42f0-6eb1-4d4b-b3bc-ea6db6a68dfb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_05d4c069-6b39-4ab3-9fd0-c2d7bac60c0a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_f8ab42f0-6eb1-4d4b-b3bc-ea6db6a68dfb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansPayableMember_fd9e5ce3-b806-40c6-bb8b-bb63aa5ecf8b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansPayableMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_f8ab42f0-6eb1-4d4b-b3bc-ea6db6a68dfb" xlink:to="loc_us-gaap_LoansPayableMember_fd9e5ce3-b806-40c6-bb8b-bb63aa5ecf8b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_32c3cfa2-bf34-4073-8973-fa25ca360aa5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentTable_98e62e15-304e-4885-b31a-5d4dd90e3e83" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_32c3cfa2-bf34-4073-8973-fa25ca360aa5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_4b882dce-1df2-49e5-8015-d10e29766cd7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_32c3cfa2-bf34-4073-8973-fa25ca360aa5" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_4b882dce-1df2-49e5-8015-d10e29766cd7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_d69d5baa-cfa6-430b-a54f-8fe6203a5a0e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodOneMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_4b882dce-1df2-49e5-8015-d10e29766cd7" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodOneMember_d69d5baa-cfa6-430b-a54f-8fe6203a5a0e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_600a2348-67ae-4dfe-9437-39ea168fec5a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodTwoMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_4b882dce-1df2-49e5-8015-d10e29766cd7" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_600a2348-67ae-4dfe-9437-39ea168fec5a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodThreeMember_2cd487f8-3d3b-4c38-ade4-ed0959569a30" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodThreeMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_4b882dce-1df2-49e5-8015-d10e29766cd7" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodThreeMember_2cd487f8-3d3b-4c38-ade4-ed0959569a30" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_6ed76b9c-f2a5-4829-9c88-ef50081be900" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentTable_98e62e15-304e-4885-b31a-5d4dd90e3e83" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_6ed76b9c-f2a5-4829-9c88-ef50081be900" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_65039766-77b8-4616-808e-4fc07fa174ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_6ed76b9c-f2a5-4829-9c88-ef50081be900" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_65039766-77b8-4616-808e-4fc07fa174ae" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_2e97e4c2-8449-47d4-9ef4-d28d7d07da61" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_65039766-77b8-4616-808e-4fc07fa174ae" xlink:to="loc_us-gaap_SubsequentEventMember_2e97e4c2-8449-47d4-9ef4-d28d7d07da61" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_23d162d8-1de3-4d98-86b7-4982ea9a16f6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentTable_98e62e15-304e-4885-b31a-5d4dd90e3e83" xlink:to="loc_us-gaap_DebtInstrumentLineItems_23d162d8-1de3-4d98-86b7-4982ea9a16f6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_925b91ee-931f-4630-a6c5-82fdb917363d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23d162d8-1de3-4d98-86b7-4982ea9a16f6" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_925b91ee-931f-4630-a6c5-82fdb917363d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_DebtInstrumentInterestPaymentExtensionTerm_4c382425-2ae7-4423-9242-29b015f39b25" xlink:href="ardx-20210630.xsd#ardx_DebtInstrumentInterestPaymentExtensionTerm"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23d162d8-1de3-4d98-86b7-4982ea9a16f6" xlink:to="loc_ardx_DebtInstrumentInterestPaymentExtensionTerm_4c382425-2ae7-4423-9242-29b015f39b25" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_DebtInstrumentClosingFeePercentage_611f349a-f08f-4657-8af1-6bb2e7455eb3" xlink:href="ardx-20210630.xsd#ardx_DebtInstrumentClosingFeePercentage"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23d162d8-1de3-4d98-86b7-4982ea9a16f6" xlink:to="loc_ardx_DebtInstrumentClosingFeePercentage_611f349a-f08f-4657-8af1-6bb2e7455eb3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_DebtInstrumentClosingFee_4728e230-51d1-45f6-8e19-9a42c2eff9d0" xlink:href="ardx-20210630.xsd#ardx_DebtInstrumentClosingFee"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23d162d8-1de3-4d98-86b7-4982ea9a16f6" xlink:to="loc_ardx_DebtInstrumentClosingFee_4728e230-51d1-45f6-8e19-9a42c2eff9d0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_DebtInstrumentFeeDueUponMaturityAccelerationPrepaymentTerminationPercentage_30c58d41-fcce-4079-b2e7-bc6a23350901" xlink:href="ardx-20210630.xsd#ardx_DebtInstrumentFeeDueUponMaturityAccelerationPrepaymentTerminationPercentage"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23d162d8-1de3-4d98-86b7-4982ea9a16f6" xlink:to="loc_ardx_DebtInstrumentFeeDueUponMaturityAccelerationPrepaymentTerminationPercentage_30c58d41-fcce-4079-b2e7-bc6a23350901" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_DebtInstrumentPrepaymentFeePercentage_3eb7ccdc-abca-46d6-8483-2036b9ebfda0" xlink:href="ardx-20210630.xsd#ardx_DebtInstrumentPrepaymentFeePercentage"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23d162d8-1de3-4d98-86b7-4982ea9a16f6" xlink:to="loc_ardx_DebtInstrumentPrepaymentFeePercentage_3eb7ccdc-abca-46d6-8483-2036b9ebfda0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_DebtInstrumentInterestRateOnDefaultPercentage_2700268d-0d5f-433d-acfb-5e1e76903917" xlink:href="ardx-20210630.xsd#ardx_DebtInstrumentInterestRateOnDefaultPercentage"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_23d162d8-1de3-4d98-86b7-4982ea9a16f6" xlink:to="loc_ardx_DebtInstrumentInterestRateOnDefaultPercentage_2700268d-0d5f-433d-acfb-5e1e76903917" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/BorrowingFuturePaymentObligationsDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#BorrowingFuturePaymentObligationsDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/BorrowingFuturePaymentObligationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract_d2cdfb5d-036e-4267-8bd8-7f41b6c43ec1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtByMaturityAbstract_3531812c-e2f0-4286-9398-4a94f854ccb0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtByMaturityAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_d2cdfb5d-036e-4267-8bd8-7f41b6c43ec1" xlink:to="loc_us-gaap_LongTermDebtByMaturityAbstract_3531812c-e2f0-4286-9398-4a94f854ccb0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_5260154d-1d65-46e8-8922-30f9cf84e99d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_3531812c-e2f0-4286-9398-4a94f854ccb0" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_5260154d-1d65-46e8-8922-30f9cf84e99d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_14fbe879-2864-4eef-8b7e-5078f1d08747" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_3531812c-e2f0-4286-9398-4a94f854ccb0" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_14fbe879-2864-4eef-8b7e-5078f1d08747" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFeeAmount_09091d28-ada9-4473-8f1e-08ec596a809e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFeeAmount"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_3531812c-e2f0-4286-9398-4a94f854ccb0" xlink:to="loc_us-gaap_DebtInstrumentFeeAmount_09091d28-ada9-4473-8f1e-08ec596a809e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_900c7e5e-9287-49e5-be8a-aba2b6aecdcb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_3531812c-e2f0-4286-9398-4a94f854ccb0" xlink:to="loc_us-gaap_LongTermDebt_900c7e5e-9287-49e5-be8a-aba2b6aecdcb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansPayableCurrent_8aa967cf-b8b3-410b-a25e-cec6630f2866" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LoansPayableCurrent"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_3531812c-e2f0-4286-9398-4a94f854ccb0" xlink:to="loc_us-gaap_LoansPayableCurrent_8aa967cf-b8b3-410b-a25e-cec6630f2866" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermLoansPayable_196b98d6-fef0-4243-adde-0410db336137" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermLoansPayable"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_3531812c-e2f0-4286-9398-4a94f854ccb0" xlink:to="loc_us-gaap_LongTermLoansPayable_196b98d6-fef0-4243-adde-0410db336137" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/BorrowingFuturePaymentObligationsDetails_1" xlink:type="simple" xlink:href="ardx-20210630.xsd#BorrowingFuturePaymentObligationsDetails_1"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/BorrowingFuturePaymentObligationsDetails_1" xlink:type="extended"/>
  <link:roleRef roleURI="http://www.ardelyx.com/role/DerivativeLiability" xlink:type="simple" xlink:href="ardx-20210630.xsd#DerivativeLiability"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/DerivativeLiability" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_001e6c9a-add2-4a33-bbc7-f56c796ccc87" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_be569e3e-97a8-4cab-b6bd-27955f873b77" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_001e6c9a-add2-4a33-bbc7-f56c796ccc87" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_be569e3e-97a8-4cab-b6bd-27955f873b77" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/DerivativeLiabilityTables" xlink:type="simple" xlink:href="ardx-20210630.xsd#DerivativeLiabilityTables"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/DerivativeLiabilityTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_e5b27ca3-48ed-43f2-964b-c05d49dce9bc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock_39a6fedf-59b4-4202-ab98-c7c2449ab4a3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_e5b27ca3-48ed-43f2-964b-c05d49dce9bc" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock_39a6fedf-59b4-4202-ab98-c7c2449ab4a3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/DerivativeLiabilityNarrativeDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#DerivativeLiabilityNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/DerivativeLiabilityNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_71ccdfe9-577b-4482-9316-6485811b9a46" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_3fd03313-0f29-4d10-93d9-10fdb7914a24" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_71ccdfe9-577b-4482-9316-6485811b9a46" xlink:to="loc_us-gaap_DerivativeTable_3fd03313-0f29-4d10-93d9-10fdb7914a24" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_8c3b0fde-c69e-4a7c-86e2-a9d9bbd26828" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeTable_3fd03313-0f29-4d10-93d9-10fdb7914a24" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_8c3b0fde-c69e-4a7c-86e2-a9d9bbd26828" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_64966e86-f6d2-442d-9354-bca39978ea77" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_8c3b0fde-c69e-4a7c-86e2-a9d9bbd26828" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_64966e86-f6d2-442d-9354-bca39978ea77" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherContractMember_752d5d28-1691-4ea2-972d-990d78766f87" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherContractMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_64966e86-f6d2-442d-9354-bca39978ea77" xlink:to="loc_us-gaap_OtherContractMember_752d5d28-1691-4ea2-972d-990d78766f87" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6ff20753-8bf4-45fc-87f8-ec9d3d0f8860" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeTable_3fd03313-0f29-4d10-93d9-10fdb7914a24" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6ff20753-8bf4-45fc-87f8-ec9d3d0f8860" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73360178-d9c9-4c45-a706-877df90f0939" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_6ff20753-8bf4-45fc-87f8-ec9d3d0f8860" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73360178-d9c9-4c45-a706-877df90f0939" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_f9b8c77a-e8ea-4d25-83fb-502341a7ddc6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73360178-d9c9-4c45-a706-877df90f0939" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_f9b8c77a-e8ea-4d25-83fb-502341a7ddc6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_0cc18745-66d9-404a-864c-4c0f2f6f5d3e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeTable_3fd03313-0f29-4d10-93d9-10fdb7914a24" xlink:to="loc_us-gaap_DerivativeLineItems_0cc18745-66d9-404a-864c-4c0f2f6f5d3e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNotionalAmount_1256789a-71ac-41b5-aec5-e747372cfe25" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeLiabilityNotionalAmount"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeLineItems_0cc18745-66d9-404a-864c-4c0f2f6f5d3e" xlink:to="loc_us-gaap_DerivativeLiabilityNotionalAmount_1256789a-71ac-41b5-aec5-e747372cfe25" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_FairValueSensitivityAnalysisChangeInProbabilityOfOccurrencePercentage_358a2dfc-fc71-40ae-b69d-7aa3f6954d9f" xlink:href="ardx-20210630.xsd#ardx_FairValueSensitivityAnalysisChangeInProbabilityOfOccurrencePercentage"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeLineItems_0cc18745-66d9-404a-864c-4c0f2f6f5d3e" xlink:to="loc_ardx_FairValueSensitivityAnalysisChangeInProbabilityOfOccurrencePercentage_358a2dfc-fc71-40ae-b69d-7aa3f6954d9f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_FairValueSensitivityAnalysisTenPercentChangeInProbabilityOfOccurrenceEffectOnValuation_f394f67a-ca87-4aca-93fc-03adfc6c0c26" xlink:href="ardx-20210630.xsd#ardx_FairValueSensitivityAnalysisTenPercentChangeInProbabilityOfOccurrenceEffectOnValuation"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeLineItems_0cc18745-66d9-404a-864c-4c0f2f6f5d3e" xlink:to="loc_ardx_FairValueSensitivityAnalysisTenPercentChangeInProbabilityOfOccurrenceEffectOnValuation_f394f67a-ca87-4aca-93fc-03adfc6c0c26" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/DerivativeLiabilityChangesinFairValueDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#DerivativeLiabilityChangesinFairValueDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/DerivativeLiabilityChangesinFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_e9ae384f-44ec-4721-81e5-fc0525804372" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_7c4a90b1-f502-4122-8136-ca0e6394bc1c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_e9ae384f-44ec-4721-81e5-fc0525804372" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_7c4a90b1-f502-4122-8136-ca0e6394bc1c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_a9f39df7-6725-4492-9d66-2afa2bd46b78" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_7c4a90b1-f502-4122-8136-ca0e6394bc1c" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_a9f39df7-6725-4492-9d66-2afa2bd46b78" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_e59a096f-e2b9-49aa-b0b0-3e102f017f7c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_a9f39df7-6725-4492-9d66-2afa2bd46b78" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_e59a096f-e2b9-49aa-b0b0-3e102f017f7c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember_f8ce802b-b003-4146-b6a7-970a8a425754" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_e59a096f-e2b9-49aa-b0b0-3e102f017f7c" xlink:to="loc_us-gaap_DerivativeFinancialInstrumentsLiabilitiesMember_f8ce802b-b003-4146-b6a7-970a8a425754" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_bb8782f2-9965-44ae-aae0-67fd4414c318" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_7c4a90b1-f502-4122-8136-ca0e6394bc1c" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_bb8782f2-9965-44ae-aae0-67fd4414c318" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_984c2c60-85bd-4d85-99db-9c0c3523e60b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_bb8782f2-9965-44ae-aae0-67fd4414c318" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_984c2c60-85bd-4d85-99db-9c0c3523e60b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_2b28151f-ffe7-4a80-bd07-bdfc9f467893" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_984c2c60-85bd-4d85-99db-9c0c3523e60b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_2b28151f-ffe7-4a80-bd07-bdfc9f467893" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_177ce4d1-e1cd-4179-9fd9-2b85cfc37024" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_984c2c60-85bd-4d85-99db-9c0c3523e60b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_177ce4d1-e1cd-4179-9fd9-2b85cfc37024" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_fd24591a-e15e-44fc-890c-dc50add808c6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_984c2c60-85bd-4d85-99db-9c0c3523e60b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_fd24591a-e15e-44fc-890c-dc50add808c6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/Leases" xlink:type="simple" xlink:href="ardx-20210630.xsd#Leases"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/Leases" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_0d4f0c99-b9fd-4f5d-9e62-0c1a21058055" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeasesTextBlock_b70288b5-6cc4-4915-9141-41f18a38b5b2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeasesTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_0d4f0c99-b9fd-4f5d-9e62-0c1a21058055" xlink:to="loc_us-gaap_LesseeOperatingLeasesTextBlock_b70288b5-6cc4-4915-9141-41f18a38b5b2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/LeasesTables" xlink:type="simple" xlink:href="ardx-20210630.xsd#LeasesTables"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/LeasesTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_27cdad42-839b-4af2-9d78-f8e581656664" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_ScheduleOfAdditionalDetailsOfLeasesTableTextBlock_f3c27567-dc95-4a10-a05f-0298cf7a67d1" xlink:href="ardx-20210630.xsd#ardx_ScheduleOfAdditionalDetailsOfLeasesTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_27cdad42-839b-4af2-9d78-f8e581656664" xlink:to="loc_ardx_ScheduleOfAdditionalDetailsOfLeasesTableTextBlock_f3c27567-dc95-4a10-a05f-0298cf7a67d1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCostTableTextBlock_a9753cd2-d1e3-469e-bfd6-5d41d8446e76" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseCostTableTextBlock"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_27cdad42-839b-4af2-9d78-f8e581656664" xlink:to="loc_us-gaap_LeaseCostTableTextBlock_a9753cd2-d1e3-469e-bfd6-5d41d8446e76" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_74a68324-5cf2-46e0-9849-754b49cae5e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_27cdad42-839b-4af2-9d78-f8e581656664" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_74a68324-5cf2-46e0-9849-754b49cae5e9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/LeasesNarrativeDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#LeasesNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/LeasesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_bcbac060-38aa-4aff-8b8b-50bcbc56f9b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_7d4d9be3-e86a-4752-8916-7be5d0c377ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_bcbac060-38aa-4aff-8b8b-50bcbc56f9b6" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_7d4d9be3-e86a-4752-8916-7be5d0c377ce" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermAxis_e8ebdf51-6b3c-494c-b789-bdeafa92192c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseContractualTermAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_7d4d9be3-e86a-4752-8916-7be5d0c377ce" xlink:to="loc_us-gaap_LeaseContractualTermAxis_e8ebdf51-6b3c-494c-b789-bdeafa92192c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermDomain_45979410-cf24-49bb-96ca-51e077ce36a2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseContractualTermDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeaseContractualTermAxis_e8ebdf51-6b3c-494c-b789-bdeafa92192c" xlink:to="loc_us-gaap_LeaseContractualTermDomain_45979410-cf24-49bb-96ca-51e077ce36a2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LeaseArrangementsAxis_1d881520-dd54-459d-a6af-3da731646eb2" xlink:href="ardx-20210630.xsd#ardx_LeaseArrangementsAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_7d4d9be3-e86a-4752-8916-7be5d0c377ce" xlink:to="loc_ardx_LeaseArrangementsAxis_1d881520-dd54-459d-a6af-3da731646eb2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LeaseArrangementsDomain_53be5efa-18ac-496e-b27b-9af3925ecfff" xlink:href="ardx-20210630.xsd#ardx_LeaseArrangementsDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_LeaseArrangementsAxis_1d881520-dd54-459d-a6af-3da731646eb2" xlink:to="loc_ardx_LeaseArrangementsDomain_53be5efa-18ac-496e-b27b-9af3925ecfff" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_FacilityFremontCaliforniaMember_f4e865bc-5d74-4cdc-b264-7f56d3001d84" xlink:href="ardx-20210630.xsd#ardx_FacilityFremontCaliforniaMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_LeaseArrangementsDomain_53be5efa-18ac-496e-b27b-9af3925ecfff" xlink:to="loc_ardx_FacilityFremontCaliforniaMember_f4e865bc-5d74-4cdc-b264-7f56d3001d84" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_FacilityWalthamMassachusettsMember_86355969-a376-4854-95ce-e1d34cba7760" xlink:href="ardx-20210630.xsd#ardx_FacilityWalthamMassachusettsMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_ardx_LeaseArrangementsDomain_53be5efa-18ac-496e-b27b-9af3925ecfff" xlink:to="loc_ardx_FacilityWalthamMassachusettsMember_86355969-a376-4854-95ce-e1d34cba7760" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_19b121c7-6533-4a09-b14b-b84c23db60b2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_7d4d9be3-e86a-4752-8916-7be5d0c377ce" xlink:to="loc_us-gaap_LesseeLeaseDescriptionLineItems_19b121c7-6533-4a09-b14b-b84c23db60b2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_58bd346d-5323-4384-afbf-1790a2d0bd2f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_19b121c7-6533-4a09-b14b-b84c23db60b2" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_58bd346d-5323-4384-afbf-1790a2d0bd2f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_568ab977-2a4f-4b2a-8e44-a202236f82db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_19b121c7-6533-4a09-b14b-b84c23db60b2" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_568ab977-2a4f-4b2a-8e44-a202236f82db" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseExistenceOfOptionToExtend_662ffdba-8640-4718-abfe-67dfa0d8ccf1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseExistenceOfOptionToExtend"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_19b121c7-6533-4a09-b14b-b84c23db60b2" xlink:to="loc_us-gaap_LesseeOperatingLeaseExistenceOfOptionToExtend_662ffdba-8640-4718-abfe-67dfa0d8ccf1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LesseeOperatingLeaseNumberOfRenewalOptions_a0ff429f-b2fe-4450-8526-8fedb077d549" xlink:href="ardx-20210630.xsd#ardx_LesseeOperatingLeaseNumberOfRenewalOptions"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_19b121c7-6533-4a09-b14b-b84c23db60b2" xlink:to="loc_ardx_LesseeOperatingLeaseNumberOfRenewalOptions_a0ff429f-b2fe-4450-8526-8fedb077d549" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_be5a0fed-ad0b-4aad-b0ef-8939317fbdca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_19b121c7-6533-4a09-b14b-b84c23db60b2" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_be5a0fed-ad0b-4aad-b0ef-8939317fbdca" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/LeasesAdditionalLeaseInformationDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#LeasesAdditionalLeaseInformationDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/LeasesAdditionalLeaseInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_7ecaba5b-617f-455f-9ae4-5266e03f2db3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAndLiabilitiesLesseeAbstract_944cf80e-c9d3-4f5d-8a5a-0be33bc856a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsAndLiabilitiesLesseeAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_7ecaba5b-617f-455f-9ae4-5266e03f2db3" xlink:to="loc_us-gaap_AssetsAndLiabilitiesLesseeAbstract_944cf80e-c9d3-4f5d-8a5a-0be33bc856a8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_a145f482-b61a-4b26-a97a-e6a2a8a82abb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAndLiabilitiesLesseeAbstract_944cf80e-c9d3-4f5d-8a5a-0be33bc856a8" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_a145f482-b61a-4b26-a97a-e6a2a8a82abb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_04c98d29-04d5-4c9c-b7f6-9ec4f3597ff0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAndLiabilitiesLesseeAbstract_944cf80e-c9d3-4f5d-8a5a-0be33bc856a8" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_04c98d29-04d5-4c9c-b7f6-9ec4f3597ff0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_f45c33bd-7c95-4753-bc6f-85b87f6e1e7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAndLiabilitiesLesseeAbstract_944cf80e-c9d3-4f5d-8a5a-0be33bc856a8" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_f45c33bd-7c95-4753-bc6f-85b87f6e1e7b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_33a87dc3-c162-48e8-abae-572778e2a435" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAndLiabilitiesLesseeAbstract_944cf80e-c9d3-4f5d-8a5a-0be33bc856a8" xlink:to="loc_us-gaap_OperatingLeaseLiability_33a87dc3-c162-48e8-abae-572778e2a435" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_915d8e7d-7c56-43a4-87a6-7afb19b7c0bc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseDescriptionAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_7ecaba5b-617f-455f-9ae4-5266e03f2db3" xlink:to="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_915d8e7d-7c56-43a4-87a6-7afb19b7c0bc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_89cf65d6-821b-4861-95b8-0df337e3e128" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_915d8e7d-7c56-43a4-87a6-7afb19b7c0bc" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_89cf65d6-821b-4861-95b8-0df337e3e128" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_dba91650-1aea-412d-9207-97e4cb3eff6a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeOperatingLeaseDescriptionAbstract_915d8e7d-7c56-43a4-87a6-7afb19b7c0bc" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_dba91650-1aea-412d-9207-97e4cb3eff6a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/LeasesLeaseCostsDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#LeasesLeaseCostsDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/LeasesLeaseCostsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_b4a500a3-9070-4deb-a395-aadbb57bc5ed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCostAbstract_c2026964-e52d-489b-aa7a-3fc01b266f33" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseCostAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_b4a500a3-9070-4deb-a395-aadbb57bc5ed" xlink:to="loc_us-gaap_LeaseCostAbstract_c2026964-e52d-489b-aa7a-3fc01b266f33" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost_00291594-a056-4800-a7ea-684a7d40f60f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseCost"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeaseCostAbstract_c2026964-e52d-489b-aa7a-3fc01b266f33" xlink:to="loc_us-gaap_OperatingLeaseCost_00291594-a056-4800-a7ea-684a7d40f60f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments_dc6c2532-bab1-4ce9-95e2-c4f875320750" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasePayments"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeaseCostAbstract_c2026964-e52d-489b-aa7a-3fc01b266f33" xlink:to="loc_us-gaap_OperatingLeasePayments_dc6c2532-bab1-4ce9-95e2-c4f875320750" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/LeasesUndiscountedCashPaymentObligationsDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#LeasesUndiscountedCashPaymentObligationsDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/LeasesUndiscountedCashPaymentObligationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_3061ca7d-627d-44b5-93e6-b634385cdc87" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_3061ca7d-627d-44b5-93e6-b634385cdc87" xlink:to="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_6ac66020-ecde-4ba2-a681-f4a5b727bc1e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_6ac66020-ecde-4ba2-a681-f4a5b727bc1e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_1f6c6dc9-57fa-44ec-b317-e93701d9c17d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_1f6c6dc9-57fa-44ec-b317-e93701d9c17d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_f322cc40-9137-45d2-8999-a0c4d10001b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_f322cc40-9137-45d2-8999-a0c4d10001b8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_8fcf750b-fbfe-4d4c-a159-c7282cc0f1c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_8fcf750b-fbfe-4d4c-a159-c7282cc0f1c7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_86cf854c-71cf-4f6d-a679-73f006fdbbba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_86cf854c-71cf-4f6d-a679-73f006fdbbba" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour_df35bc35-8653-4f55-860e-d5982c5e5681" xlink:href="ardx-20210630.xsd#ardx_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_ardx_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour_df35bc35-8653-4f55-860e-d5982c5e5681" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_63dbebb1-41bc-46d2-9799-52ae18bfa78a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_63dbebb1-41bc-46d2-9799-52ae18bfa78a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_0af67a51-1f27-4f11-b25f-bcdd9ad94851" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_0af67a51-1f27-4f11-b25f-bcdd9ad94851" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_f0bcac8d-3144-4ccd-b7a5-44068abb44eb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_OperatingLeaseLiability_f0bcac8d-3144-4ccd-b7a5-44068abb44eb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_4c1f094c-09c6-441a-8621-d0e877ba9d27" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_4c1f094c-09c6-441a-8621-d0e877ba9d27" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_af2898e5-8a1a-4dc2-9bea-42670a9df104" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_7b63b934-c090-4bba-a317-80565c717e49" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_af2898e5-8a1a-4dc2-9bea-42670a9df104" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/LeasesUndiscountedCashPaymentObligationsDetails_1" xlink:type="simple" xlink:href="ardx-20210630.xsd#LeasesUndiscountedCashPaymentObligationsDetails_1"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/LeasesUndiscountedCashPaymentObligationsDetails_1" xlink:type="extended"/>
  <link:roleRef roleURI="http://www.ardelyx.com/role/StockholdersEquity" xlink:type="simple" xlink:href="ardx-20210630.xsd#StockholdersEquity"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/StockholdersEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityNoteAbstract_98e98b14-01a9-4fe3-8cc6-3e32c37e76b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityNoteAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock_739de35a-4b8f-405b-b336-e3cb52806abb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityNoteAbstract_98e98b14-01a9-4fe3-8cc6-3e32c37e76b6" xlink:to="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock_739de35a-4b8f-405b-b336-e3cb52806abb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/StockholdersEquityDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#StockholdersEquityDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/StockholdersEquityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityNoteAbstract_7f83bcf4-0fac-4b34-b1de-9bedce157e40" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquityNoteAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_c555080d-73b7-4c07-aa85-455d0ac2469a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityNoteAbstract_7f83bcf4-0fac-4b34-b1de-9bedce157e40" xlink:to="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_c555080d-73b7-4c07-aa85-455d0ac2469a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_705981d8-25df-47ee-aab6-304673360978" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_c555080d-73b7-4c07-aa85-455d0ac2469a" xlink:to="loc_us-gaap_StatementClassOfStockAxis_705981d8-25df-47ee-aab6-304673360978" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_88a1021f-bce7-4def-9c1c-b78630519001" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementClassOfStockAxis_705981d8-25df-47ee-aab6-304673360978" xlink:to="loc_us-gaap_ClassOfStockDomain_88a1021f-bce7-4def-9c1c-b78630519001" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonClassAMember_d3180397-db1f-4c46-a58f-1588590b50a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonClassAMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ClassOfStockDomain_88a1021f-bce7-4def-9c1c-b78630519001" xlink:to="loc_us-gaap_CommonClassAMember_d3180397-db1f-4c46-a58f-1588590b50a5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_8c278781-aba9-476d-94dd-e44a690a67ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_c555080d-73b7-4c07-aa85-455d0ac2469a" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_8c278781-aba9-476d-94dd-e44a690a67ce" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_b5929b59-ff01-4785-a757-8a8afa756cf7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_8c278781-aba9-476d-94dd-e44a690a67ce" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_b5929b59-ff01-4785-a757-8a8afa756cf7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_AtMarketOfferingMember_b70b6e42-7646-469b-9f20-804273d25975" xlink:href="ardx-20210630.xsd#ardx_AtMarketOfferingMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_b5929b59-ff01-4785-a757-8a8afa756cf7" xlink:to="loc_ardx_AtMarketOfferingMember_b70b6e42-7646-469b-9f20-804273d25975" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockLineItems_97141925-ad21-42a3-82b2-f5814eae48b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsidiarySaleOfStockLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiaryOrEquityMethodInvesteeSaleOfStockBySubsidiaryOrEquityInvesteeTable_c555080d-73b7-4c07-aa85-455d0ac2469a" xlink:to="loc_us-gaap_SubsidiarySaleOfStockLineItems_97141925-ad21-42a3-82b2-f5814eae48b7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_MaximumAggregateOfferingPrice_4cce9aa9-917f-4ee5-9b38-4878f8b9e787" xlink:href="ardx-20210630.xsd#ardx_MaximumAggregateOfferingPrice"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_97141925-ad21-42a3-82b2-f5814eae48b7" xlink:to="loc_ardx_MaximumAggregateOfferingPrice_4cce9aa9-917f-4ee5-9b38-4878f8b9e787" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_7b1a5fc3-254c-4bfe-a9ad-b4f033af4cb1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_97141925-ad21-42a3-82b2-f5814eae48b7" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_7b1a5fc3-254c-4bfe-a9ad-b4f033af4cb1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_8569dbef-4c3f-4a3f-99e8-56623a22e3ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_97141925-ad21-42a3-82b2-f5814eae48b7" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommonStock_8569dbef-4c3f-4a3f-99e8-56623a22e3ee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_SaleOfStockWeightedAveragePricePerShare_6cda0b5e-2e07-49bc-8566-36db5ddfa72c" xlink:href="ardx-20210630.xsd#ardx_SaleOfStockWeightedAveragePricePerShare"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_97141925-ad21-42a3-82b2-f5814eae48b7" xlink:to="loc_ardx_SaleOfStockWeightedAveragePricePerShare_6cda0b5e-2e07-49bc-8566-36db5ddfa72c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_StockIssuanceCostCommissionPercent_37ceb1a0-f4e9-4cbf-9a41-ba1c2397ae9a" xlink:href="ardx-20210630.xsd#ardx_StockIssuanceCostCommissionPercent"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiarySaleOfStockLineItems_97141925-ad21-42a3-82b2-f5814eae48b7" xlink:to="loc_ardx_StockIssuanceCostCommissionPercent_37ceb1a0-f4e9-4cbf-9a41-ba1c2397ae9a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/EquityIncentivePlans" xlink:type="simple" xlink:href="ardx-20210630.xsd#EquityIncentivePlans"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/EquityIncentivePlans" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_ea111846-2594-4873-acc2-35fd8e6c00fd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_d3255109-249f-4f7f-ae86-193102260864" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_ea111846-2594-4873-acc2-35fd8e6c00fd" xlink:to="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_d3255109-249f-4f7f-ae86-193102260864" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/EquityIncentivePlansTables" xlink:type="simple" xlink:href="ardx-20210630.xsd#EquityIncentivePlansTables"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/EquityIncentivePlansTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_0f361716-d846-41b5-9821-2f0ad7ac59be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_bdf3aebc-64b3-4af2-98ab-2f6a10a872ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_0f361716-d846-41b5-9821-2f0ad7ac59be" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_bdf3aebc-64b3-4af2-98ab-2f6a10a872ee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfUnrecognizedCompensationCostNonvestedAwardsTableTextBlock_0d68cd1a-b96d-412b-be23-27af8830aaef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfUnrecognizedCompensationCostNonvestedAwardsTableTextBlock"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_0f361716-d846-41b5-9821-2f0ad7ac59be" xlink:to="loc_us-gaap_ScheduleOfUnrecognizedCompensationCostNonvestedAwardsTableTextBlock_0d68cd1a-b96d-412b-be23-27af8830aaef" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_3925abc4-4ca4-48b1-a057-3d64c0a1e1b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_0f361716-d846-41b5-9821-2f0ad7ac59be" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_3925abc4-4ca4-48b1-a057-3d64c0a1e1b8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock_7aae1e46-f622-441a-adf1-5dca2227ce62" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_0f361716-d846-41b5-9821-2f0ad7ac59be" xlink:to="loc_us-gaap_ScheduleOfNonvestedRestrictedStockUnitsActivityTableTextBlock_7aae1e46-f622-441a-adf1-5dca2227ce62" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/EquityIncentivePlansStockBasedCompensationDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#EquityIncentivePlansStockBasedCompensationDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/EquityIncentivePlansStockBasedCompensationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_b4c8a105-06c7-4043-90bb-6b03bef840f1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_3492a522-95fd-452f-8dab-b2977bcf66c6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_b4c8a105-06c7-4043-90bb-6b03bef840f1" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_3492a522-95fd-452f-8dab-b2977bcf66c6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_07771c06-2574-4784-b8c5-8f005c403a5a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_3492a522-95fd-452f-8dab-b2977bcf66c6" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_07771c06-2574-4784-b8c5-8f005c403a5a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_ff4cc28d-e667-48eb-9ae8-4b1cd696030e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_07771c06-2574-4784-b8c5-8f005c403a5a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_ff4cc28d-e667-48eb-9ae8-4b1cd696030e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_999ece14-f039-4a56-b0b8-43105a489f60" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_ff4cc28d-e667-48eb-9ae8-4b1cd696030e" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_999ece14-f039-4a56-b0b8-43105a489f60" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_21cf68df-3fb9-4900-877c-f4c075ab4bd4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_ff4cc28d-e667-48eb-9ae8-4b1cd696030e" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_21cf68df-3fb9-4900-877c-f4c075ab4bd4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_50bcda1f-d1de-4045-9e99-ba7b4344c9ff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_3492a522-95fd-452f-8dab-b2977bcf66c6" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_50bcda1f-d1de-4045-9e99-ba7b4344c9ff" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_73e3ae6e-b4af-4ded-997b-adb2f3761e0e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_50bcda1f-d1de-4045-9e99-ba7b4344c9ff" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_73e3ae6e-b4af-4ded-997b-adb2f3761e0e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/EquityIncentivePlansUnrecognizedStockBasedCompensationDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#EquityIncentivePlansUnrecognizedStockBasedCompensationDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/EquityIncentivePlansUnrecognizedStockBasedCompensationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_56d30777-a499-4523-9a34-91899743c4cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_c3e7b47e-07e7-412e-97d0-a0da0533b8fe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_56d30777-a499-4523-9a34-91899743c4cb" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_c3e7b47e-07e7-412e-97d0-a0da0533b8fe" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_d4e2b07d-ec12-4abf-beca-e878a840b6c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_c3e7b47e-07e7-412e-97d0-a0da0533b8fe" xlink:to="loc_us-gaap_PlanNameAxis_d4e2b07d-ec12-4abf-beca-e878a840b6c9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_df359348-3434-4d01-9557-9024ecc232e7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameAxis_d4e2b07d-ec12-4abf-beca-e878a840b6c9" xlink:to="loc_us-gaap_PlanNameDomain_df359348-3434-4d01-9557-9024ecc232e7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_EmployeeStockPurchasePlanMember_8661615f-c37f-49b7-969c-003ed12acd6f" xlink:href="ardx-20210630.xsd#ardx_EmployeeStockPurchasePlanMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_df359348-3434-4d01-9557-9024ecc232e7" xlink:to="loc_ardx_EmployeeStockPurchasePlanMember_8661615f-c37f-49b7-969c-003ed12acd6f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_47ad1975-3f9e-4266-8aaa-ca5610e0a903" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_c3e7b47e-07e7-412e-97d0-a0da0533b8fe" xlink:to="loc_us-gaap_AwardTypeAxis_47ad1975-3f9e-4266-8aaa-ca5610e0a903" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0279a2dc-a706-47f3-a39c-8718e86b0658" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_47ad1975-3f9e-4266-8aaa-ca5610e0a903" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0279a2dc-a706-47f3-a39c-8718e86b0658" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_d060340e-a2bf-4daa-89f9-f53f7f144892" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0279a2dc-a706-47f3-a39c-8718e86b0658" xlink:to="loc_us-gaap_EmployeeStockOptionMember_d060340e-a2bf-4daa-89f9-f53f7f144892" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_b17c64bc-2f5d-42a2-8400-e55b0ffb03c5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0279a2dc-a706-47f3-a39c-8718e86b0658" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_b17c64bc-2f5d-42a2-8400-e55b0ffb03c5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ed71ce3d-e9da-47c7-9776-0250a3700e49" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_c3e7b47e-07e7-412e-97d0-a0da0533b8fe" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ed71ce3d-e9da-47c7-9776-0250a3700e49" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_06f649f3-0165-47c0-9775-e2b96edd6eca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ed71ce3d-e9da-47c7-9776-0250a3700e49" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_06f649f3-0165-47c0-9775-e2b96edd6eca" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_486c5d82-06eb-4ad6-a34e-ce8b3cd89e61" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ed71ce3d-e9da-47c7-9776-0250a3700e49" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_486c5d82-06eb-4ad6-a34e-ce8b3cd89e61" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/EquityIncentivePlansStockOptionsDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#EquityIncentivePlansStockOptionsDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/EquityIncentivePlansStockOptionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_1337845a-4004-40ee-933c-edb0422c8498" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_27f9de49-cc95-4015-b632-98f11da4c7f0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_1337845a-4004-40ee-933c-edb0422c8498" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_27f9de49-cc95-4015-b632-98f11da4c7f0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_14184b17-62e4-49f9-8ad3-b849cba9a624" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_27f9de49-cc95-4015-b632-98f11da4c7f0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_14184b17-62e4-49f9-8ad3-b849cba9a624" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_b48bc131-8f4f-4d5f-b246-ede11946058b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_27f9de49-cc95-4015-b632-98f11da4c7f0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_b48bc131-8f4f-4d5f-b246-ede11946058b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_41080a79-11d2-4d44-8be6-d8fe06c85a83" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_27f9de49-cc95-4015-b632-98f11da4c7f0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_41080a79-11d2-4d44-8be6-d8fe06c85a83" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_e7f3a365-2d9f-4e63-9473-a1e7fb4fd0df" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_27f9de49-cc95-4015-b632-98f11da4c7f0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_e7f3a365-2d9f-4e63-9473-a1e7fb4fd0df" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_a280914a-67af-48b4-a6dc-4075082c00bd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_27f9de49-cc95-4015-b632-98f11da4c7f0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_a280914a-67af-48b4-a6dc-4075082c00bd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_2dd4b1b8-d3d7-4c7e-a8da-f86741d434ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_1337845a-4004-40ee-933c-edb0422c8498" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_2dd4b1b8-d3d7-4c7e-a8da-f86741d434ae" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_a682050f-cf1c-4c2f-9c30-bd5755426ac1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_1337845a-4004-40ee-933c-edb0422c8498" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_a682050f-cf1c-4c2f-9c30-bd5755426ac1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_84a3a0c9-ca0f-416c-8551-2d5529bade7e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_a682050f-cf1c-4c2f-9c30-bd5755426ac1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_84a3a0c9-ca0f-416c-8551-2d5529bade7e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_1d40632c-c719-4984-8eed-45bcc74a2998" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_a682050f-cf1c-4c2f-9c30-bd5755426ac1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_1d40632c-c719-4984-8eed-45bcc74a2998" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_fabfb6e7-165e-459d-95e9-a4e7e16b1d25" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_a682050f-cf1c-4c2f-9c30-bd5755426ac1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_fabfb6e7-165e-459d-95e9-a4e7e16b1d25" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_a86b4283-38bd-467f-b11a-d8e5463d53bd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_a682050f-cf1c-4c2f-9c30-bd5755426ac1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_a86b4283-38bd-467f-b11a-d8e5463d53bd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_69abdfb1-4e50-4a6b-94d8-71e7262834cd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_a682050f-cf1c-4c2f-9c30-bd5755426ac1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_69abdfb1-4e50-4a6b-94d8-71e7262834cd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_3b7d60b1-964d-4c64-9b0f-3a0ae5766843" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_1337845a-4004-40ee-933c-edb0422c8498" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_3b7d60b1-964d-4c64-9b0f-3a0ae5766843" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/EquityIncentivePlansRestrictedStockUnitsDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#EquityIncentivePlansRestrictedStockUnitsDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/EquityIncentivePlansRestrictedStockUnitsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_73102453-7cad-448c-81a1-843767bee86b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_121b8ee6-dc36-49f2-b720-7132195b129c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_73102453-7cad-448c-81a1-843767bee86b" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_121b8ee6-dc36-49f2-b720-7132195b129c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_dbdbcc66-bcae-4b9a-83bd-5a68d76d2b46" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_121b8ee6-dc36-49f2-b720-7132195b129c" xlink:to="loc_us-gaap_AwardTypeAxis_dbdbcc66-bcae-4b9a-83bd-5a68d76d2b46" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d6a18db8-4da0-4ae4-8dda-3509bc7831e1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_dbdbcc66-bcae-4b9a-83bd-5a68d76d2b46" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d6a18db8-4da0-4ae4-8dda-3509bc7831e1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_60bfb197-6422-42cd-9967-88a1fa982d98" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d6a18db8-4da0-4ae4-8dda-3509bc7831e1" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_60bfb197-6422-42cd-9967-88a1fa982d98" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b44ae52a-4d9c-4a92-aaaa-68ffd5c95df3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_121b8ee6-dc36-49f2-b720-7132195b129c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b44ae52a-4d9c-4a92-aaaa-68ffd5c95df3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_98ed304c-c97d-4631-99ee-3f6fb6618ce8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b44ae52a-4d9c-4a92-aaaa-68ffd5c95df3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_98ed304c-c97d-4631-99ee-3f6fb6618ce8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_a936d85f-cce6-4bc6-a26f-017e187d626b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_98ed304c-c97d-4631-99ee-3f6fb6618ce8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_a936d85f-cce6-4bc6-a26f-017e187d626b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_0ed3028e-a819-4016-bdc6-6d32d57c61fa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_98ed304c-c97d-4631-99ee-3f6fb6618ce8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_0ed3028e-a819-4016-bdc6-6d32d57c61fa" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4adfcd02-09a5-41c3-8845-19214d3644ce" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_98ed304c-c97d-4631-99ee-3f6fb6618ce8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4adfcd02-09a5-41c3-8845-19214d3644ce" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_65e250af-a135-49b4-9264-2e7aaa96e0ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_98ed304c-c97d-4631-99ee-3f6fb6618ce8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_65e250af-a135-49b4-9264-2e7aaa96e0ae" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_0d25d21f-e458-41f5-a4fb-0e2f116a50e5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_98ed304c-c97d-4631-99ee-3f6fb6618ce8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_0d25d21f-e458-41f5-a4fb-0e2f116a50e5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_2a3ecfc8-a658-4c19-a789-6a2afa2af281" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b44ae52a-4d9c-4a92-aaaa-68ffd5c95df3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_2a3ecfc8-a658-4c19-a789-6a2afa2af281" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_b79c3ed3-0709-4526-b316-9eb22e4f447f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_2a3ecfc8-a658-4c19-a789-6a2afa2af281" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_b79c3ed3-0709-4526-b316-9eb22e4f447f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_f1dc361b-d6bd-43e0-9153-9d58b75e740d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_2a3ecfc8-a658-4c19-a789-6a2afa2af281" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_f1dc361b-d6bd-43e0-9153-9d58b75e740d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_09bcb53d-d143-422b-95ac-20b7f9c50530" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_2a3ecfc8-a658-4c19-a789-6a2afa2af281" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_09bcb53d-d143-422b-95ac-20b7f9c50530" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_f8371683-315a-4ea0-925a-ca3fef7baa94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_2a3ecfc8-a658-4c19-a789-6a2afa2af281" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_f8371683-315a-4ea0-925a-ca3fef7baa94" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_85392a6c-8e8e-479a-a9c7-5184bd2a978c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_2a3ecfc8-a658-4c19-a789-6a2afa2af281" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_85392a6c-8e8e-479a-a9c7-5184bd2a978c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/EquityIncentivePlansNarrativeDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#EquityIncentivePlansNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/EquityIncentivePlansNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_71d06346-4779-47b2-9e70-6f63c337d5fb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8e4659b8-2d51-47f6-ad7a-aa87558592a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_71d06346-4779-47b2-9e70-6f63c337d5fb" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8e4659b8-2d51-47f6-ad7a-aa87558592a8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_06d54bcb-e8c0-4bce-bba6-4f3674dad5d4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8e4659b8-2d51-47f6-ad7a-aa87558592a8" xlink:to="loc_us-gaap_AwardTypeAxis_06d54bcb-e8c0-4bce-bba6-4f3674dad5d4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e485979c-c8fb-4b9c-9cba-43dd4346e00d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_06d54bcb-e8c0-4bce-bba6-4f3674dad5d4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e485979c-c8fb-4b9c-9cba-43dd4346e00d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_PerformanceBasedRestrictedStockUnitsMember_f2704070-df04-4175-bfdb-61094ff4e54e" xlink:href="ardx-20210630.xsd#ardx_PerformanceBasedRestrictedStockUnitsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e485979c-c8fb-4b9c-9cba-43dd4346e00d" xlink:to="loc_ardx_PerformanceBasedRestrictedStockUnitsMember_f2704070-df04-4175-bfdb-61094ff4e54e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_a333293d-ece2-4c3d-8de7-a2791d5c3580" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8e4659b8-2d51-47f6-ad7a-aa87558592a8" xlink:to="loc_us-gaap_PlanNameAxis_a333293d-ece2-4c3d-8de7-a2791d5c3580" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_2fc24252-250f-4b81-ab35-da0b6868b806" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameAxis_a333293d-ece2-4c3d-8de7-a2791d5c3580" xlink:to="loc_us-gaap_PlanNameDomain_2fc24252-250f-4b81-ab35-da0b6868b806" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_EmployeeStockPurchasePlanMember_512cb764-fe95-4198-ac62-ca0e89ece5bb" xlink:href="ardx-20210630.xsd#ardx_EmployeeStockPurchasePlanMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_2fc24252-250f-4b81-ab35-da0b6868b806" xlink:to="loc_ardx_EmployeeStockPurchasePlanMember_512cb764-fe95-4198-ac62-ca0e89ece5bb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_10e36938-a20e-47e4-8676-27013e2d5ab0" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8e4659b8-2d51-47f6-ad7a-aa87558592a8" xlink:to="loc_srt_TitleOfIndividualAxis_10e36938-a20e-47e4-8676-27013e2d5ab0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_277c0d7a-72e7-4962-b92f-98996858d9e2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_TitleOfIndividualAxis_10e36938-a20e-47e4-8676-27013e2d5ab0" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_277c0d7a-72e7-4962-b92f-98996858d9e2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_DirectorMember_5e7a9abf-c561-45ca-afa6-4d42afdb5a6c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_DirectorMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_277c0d7a-72e7-4962-b92f-98996858d9e2" xlink:to="loc_srt_DirectorMember_5e7a9abf-c561-45ca-afa6-4d42afdb5a6c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5726f840-3662-485d-9f4d-c2e841f0347f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8e4659b8-2d51-47f6-ad7a-aa87558592a8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5726f840-3662-485d-9f4d-c2e841f0347f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_f5f8276a-c2f3-4754-b57b-7587c955347d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5726f840-3662-485d-9f4d-c2e841f0347f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_f5f8276a-c2f3-4754-b57b-7587c955347d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_3f2d4e9e-bb0c-4881-b85b-efff964448df" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5726f840-3662-485d-9f4d-c2e841f0347f" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_3f2d4e9e-bb0c-4881-b85b-efff964448df" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_25f9d8fb-b3ca-43d1-9da6-627186a07b77" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5726f840-3662-485d-9f4d-c2e841f0347f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_25f9d8fb-b3ca-43d1-9da6-627186a07b77" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharePrice_ab50f816-c718-4a17-9ae2-397a76161007" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharePrice"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5726f840-3662-485d-9f4d-c2e841f0347f" xlink:to="loc_us-gaap_SharePrice_ab50f816-c718-4a17-9ae2-397a76161007" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_0658b91e-b27e-4a9c-91f0-158ad3609ede" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5726f840-3662-485d-9f4d-c2e841f0347f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_0658b91e-b27e-4a9c-91f0-158ad3609ede" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_f7f24604-e9d4-4923-87e4-759dc51abb50" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5726f840-3662-485d-9f4d-c2e841f0347f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_f7f24604-e9d4-4923-87e4-759dc51abb50" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/NetLossPerShare" xlink:type="simple" xlink:href="ardx-20210630.xsd#NetLossPerShare"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/NetLossPerShare" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_0295a47c-71f8-45bc-8e82-f8228a52d261" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareTextBlock_c1c5a4a8-90ec-4ad2-bf2a-277f12a86081" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_0295a47c-71f8-45bc-8e82-f8228a52d261" xlink:to="loc_us-gaap_EarningsPerShareTextBlock_c1c5a4a8-90ec-4ad2-bf2a-277f12a86081" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/NetLossPerShareTables" xlink:type="simple" xlink:href="ardx-20210630.xsd#NetLossPerShareTables"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/NetLossPerShareTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_70fd948b-4418-4793-b39d-d6583d35dcfc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_5c9b6f7f-b92f-48d9-b7c4-e930d6a248a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_70fd948b-4418-4793-b39d-d6583d35dcfc" xlink:to="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_5c9b6f7f-b92f-48d9-b7c4-e930d6a248a4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/NetLossPerShareComputationofNetLossPerCommonShareDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#NetLossPerShareComputationofNetLossPerCommonShareDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/NetLossPerShareComputationofNetLossPerCommonShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_76b1096f-c625-439c-b616-e5bfd74cf39c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAbstract_2ba1c30c-fb62-4810-bd31-ccd7cced0c14" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_76b1096f-c625-439c-b616-e5bfd74cf39c" xlink:to="loc_us-gaap_NetIncomeLossAbstract_2ba1c30c-fb62-4810-bd31-ccd7cced0c14" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_d0142d2b-fb28-4496-b365-46ff32ce0e0b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetIncomeLossAbstract_2ba1c30c-fb62-4810-bd31-ccd7cced0c14" xlink:to="loc_us-gaap_NetIncomeLoss_d0142d2b-fb28-4496-b365-46ff32ce0e0b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_ef4895c3-b4e1-4c3e-ae49-c44dd0fde82d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_76b1096f-c625-439c-b616-e5bfd74cf39c" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_ef4895c3-b4e1-4c3e-ae49-c44dd0fde82d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_506dc4fb-0fc4-4506-82c9-d79c2451af5f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_ef4895c3-b4e1-4c3e-ae49-c44dd0fde82d" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_506dc4fb-0fc4-4506-82c9-d79c2451af5f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_f4986887-d7bf-42dc-a352-80d38918dc9e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_ef4895c3-b4e1-4c3e-ae49-c44dd0fde82d" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_f4986887-d7bf-42dc-a352-80d38918dc9e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_6964e06d-f98b-4c0d-944c-6527f53a0669" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_76b1096f-c625-439c-b616-e5bfd74cf39c" xlink:to="loc_us-gaap_EarningsPerShareBasic_6964e06d-f98b-4c0d-944c-6527f53a0669" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_c203679e-577d-4951-8772-c4e315a0e20d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_76b1096f-c625-439c-b616-e5bfd74cf39c" xlink:to="loc_us-gaap_EarningsPerShareDiluted_c203679e-577d-4951-8772-c4e315a0e20d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/NetLossPerShareNarrativeDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#NetLossPerShareNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/NetLossPerShareNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_fc33be59-4fe5-4bde-b2a8-f881dcdaea0a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_154bd636-bd30-495e-b6f5-80cc99977309" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_fc33be59-4fe5-4bde-b2a8-f881dcdaea0a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_154bd636-bd30-495e-b6f5-80cc99977309" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/Contingencies" xlink:type="simple" xlink:href="ardx-20210630.xsd#Contingencies"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/Contingencies" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_e5118f60-7421-4603-91d6-75778f358e36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_6d22e331-0c8e-4bcb-9fc3-92b40be47d91" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_e5118f60-7421-4603-91d6-75778f358e36" xlink:to="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_6d22e331-0c8e-4bcb-9fc3-92b40be47d91" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/ContingenciesDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#ContingenciesDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/ContingenciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_b1f90c62-7b90-439d-813b-4e582274d1f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyAccrualAtCarryingValue_b6f96202-76e9-431a-8ff2-01f84832884c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyAccrualAtCarryingValue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_b1f90c62-7b90-439d-813b-4e582274d1f4" xlink:to="loc_us-gaap_LossContingencyAccrualAtCarryingValue_b6f96202-76e9-431a-8ff2-01f84832884c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/SubsequentEvents" xlink:type="simple" xlink:href="ardx-20210630.xsd#SubsequentEvents"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/SubsequentEvents" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventsAbstract_31521c4a-cb44-46ca-b0e9-53d84c2e6435" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventsTextBlock_ac90ad01-94ac-4494-8c7a-698c8edd4b78" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventsTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventsAbstract_31521c4a-cb44-46ca-b0e9-53d84c2e6435" xlink:to="loc_us-gaap_SubsequentEventsTextBlock_ac90ad01-94ac-4494-8c7a-698c8edd4b78" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.ardelyx.com/role/SubsequentEventsDetails" xlink:type="simple" xlink:href="ardx-20210630.xsd#SubsequentEventsDetails"/>
  <link:presentationLink xlink:role="http://www.ardelyx.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventsAbstract_3cd9690b-0e16-43fc-84f6-9f2b6d3a9fbf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_c8d1cba8-67ff-49d7-9b46-b5f3f5ccf912" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventsAbstract_3cd9690b-0e16-43fc-84f6-9f2b6d3a9fbf" xlink:to="loc_us-gaap_SubsequentEventTable_c8d1cba8-67ff-49d7-9b46-b5f3f5ccf912" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_144314af-1eee-4e62-b068-030c02da4852" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_c8d1cba8-67ff-49d7-9b46-b5f3f5ccf912" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_144314af-1eee-4e62-b068-030c02da4852" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_434b4f86-0bf6-4d17-9f9a-79af9bc04ba2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_144314af-1eee-4e62-b068-030c02da4852" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_434b4f86-0bf6-4d17-9f9a-79af9bc04ba2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_2f32f26b-40d0-47e4-86c2-334a0f2d5a04" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_434b4f86-0bf6-4d17-9f9a-79af9bc04ba2" xlink:to="loc_us-gaap_SubsequentEventMember_2f32f26b-40d0-47e4-86c2-334a0f2d5a04" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_ede75f3d-1221-4a9b-882b-4a6070de1940" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_c8d1cba8-67ff-49d7-9b46-b5f3f5ccf912" xlink:to="loc_srt_LitigationCaseAxis_ede75f3d-1221-4a9b-882b-4a6070de1940" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_780360e5-b06c-416d-8893-91a4cb5f73d7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_LitigationCaseAxis_ede75f3d-1221-4a9b-882b-4a6070de1940" xlink:to="loc_srt_LitigationCaseTypeDomain_780360e5-b06c-416d-8893-91a4cb5f73d7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_PutativeSecuritiesClassActionLawsuitMember_587ecf92-5f4d-43b8-beb4-d95aa97dd7e5" xlink:href="ardx-20210630.xsd#ardx_PutativeSecuritiesClassActionLawsuitMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_LitigationCaseTypeDomain_780360e5-b06c-416d-8893-91a4cb5f73d7" xlink:to="loc_ardx_PutativeSecuritiesClassActionLawsuitMember_587ecf92-5f4d-43b8-beb4-d95aa97dd7e5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusAxis_7e34e053-430f-480c-aab6-f7c54d060f99" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_c8d1cba8-67ff-49d7-9b46-b5f3f5ccf912" xlink:to="loc_us-gaap_LitigationStatusAxis_7e34e053-430f-480c-aab6-f7c54d060f99" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_8313c596-f110-4c5a-a788-9790143e224e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LitigationStatusAxis_7e34e053-430f-480c-aab6-f7c54d060f99" xlink:to="loc_us-gaap_LitigationStatusDomain_8313c596-f110-4c5a-a788-9790143e224e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PendingLitigationMember_f1cd5c5b-c491-4349-8005-c927ff6c3093" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PendingLitigationMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LitigationStatusDomain_8313c596-f110-4c5a-a788-9790143e224e" xlink:to="loc_us-gaap_PendingLitigationMember_f1cd5c5b-c491-4349-8005-c927ff6c3093" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_84c1ee73-57c4-4edd-af2a-3364724941cf" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualAxis"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_c8d1cba8-67ff-49d7-9b46-b5f3f5ccf912" xlink:to="loc_srt_TitleOfIndividualAxis_84c1ee73-57c4-4edd-af2a-3364724941cf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_ce1c91d5-67ce-448b-8b60-da6716b9007e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_TitleOfIndividualAxis_84c1ee73-57c4-4edd-af2a-3364724941cf" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_ce1c91d5-67ce-448b-8b60-da6716b9007e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OfficerMember_a3610ed3-b1df-49e5-8b46-1325bf1b5062" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_OfficerMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_ce1c91d5-67ce-448b-8b60-da6716b9007e" xlink:to="loc_srt_OfficerMember_a3610ed3-b1df-49e5-8b46-1325bf1b5062" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanAxis_031e121c-006f-470d-8381-cf3d55d61e70" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestructuringPlanAxis"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_c8d1cba8-67ff-49d7-9b46-b5f3f5ccf912" xlink:to="loc_us-gaap_RestructuringPlanAxis_031e121c-006f-470d-8381-cf3d55d61e70" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanDomain_f82ef380-e335-4b5b-8975-1dfc3625115d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestructuringPlanDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringPlanAxis_031e121c-006f-470d-8381-cf3d55d61e70" xlink:to="loc_us-gaap_RestructuringPlanDomain_f82ef380-e335-4b5b-8975-1dfc3625115d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_WorkforceRealignmentMember_06efbf16-77ad-4309-bf13-bbbc47431061" xlink:href="ardx-20210630.xsd#ardx_WorkforceRealignmentMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestructuringPlanDomain_f82ef380-e335-4b5b-8975-1dfc3625115d" xlink:to="loc_ardx_WorkforceRealignmentMember_06efbf16-77ad-4309-bf13-bbbc47431061" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOnFutureEarningsAndCashFlowsResultingFromExitPlanAxis_efe45eeb-0001-419d-aefd-c75d1d2624af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectsOnFutureEarningsAndCashFlowsResultingFromExitPlanAxis"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_c8d1cba8-67ff-49d7-9b46-b5f3f5ccf912" xlink:to="loc_us-gaap_EffectsOnFutureEarningsAndCashFlowsResultingFromExitPlanAxis_efe45eeb-0001-419d-aefd-c75d1d2624af" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOnFutureEarningsAndCashFlowsByTypeOfEffectDomain_9e23132c-c27f-4510-8f60-3de4531663f8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectsOnFutureEarningsAndCashFlowsByTypeOfEffectDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EffectsOnFutureEarningsAndCashFlowsResultingFromExitPlanAxis_efe45eeb-0001-419d-aefd-c75d1d2624af" xlink:to="loc_us-gaap_EffectsOnFutureEarningsAndCashFlowsByTypeOfEffectDomain_9e23132c-c27f-4510-8f60-3de4531663f8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReducedEmployeeExpensesMember_7177eaf5-e710-4b14-82f4-aa2e704fb002" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReducedEmployeeExpensesMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EffectsOnFutureEarningsAndCashFlowsByTypeOfEffectDomain_9e23132c-c27f-4510-8f60-3de4531663f8" xlink:to="loc_us-gaap_ReducedEmployeeExpensesMember_7177eaf5-e710-4b14-82f4-aa2e704fb002" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_b9acfb65-afd6-42f2-858c-dfe8359686ba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_c8d1cba8-67ff-49d7-9b46-b5f3f5ccf912" xlink:to="loc_us-gaap_SubsequentEventLineItems_b9acfb65-afd6-42f2-858c-dfe8359686ba" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminated_9122070e-ac62-4856-89f3-deeb1ab9264e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminated"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_b9acfb65-afd6-42f2-858c-dfe8359686ba" xlink:to="loc_us-gaap_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminated_9122070e-ac62-4856-89f3-deeb1ab9264e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminatedPercentageOfWorkforce_d90680ce-6c5c-4f94-8833-3a202d6e06e3" xlink:href="ardx-20210630.xsd#ardx_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminatedPercentageOfWorkforce"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_b9acfb65-afd6-42f2-858c-dfe8359686ba" xlink:to="loc_ardx_RestructuringAndRelatedCostExpectedNumberOfPositionsEliminatedPercentageOfWorkforce_d90680ce-6c5c-4f94-8833-3a202d6e06e3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_ardx_RestructuringAndRelatedCostImpactedEmployeesTermForCashPaymentsAndBenefits_41f10245-6444-4b1d-8141-15de8a19afdd" xlink:href="ardx-20210630.xsd#ardx_RestructuringAndRelatedCostImpactedEmployeesTermForCashPaymentsAndBenefits"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_b9acfb65-afd6-42f2-858c-dfe8359686ba" xlink:to="loc_ardx_RestructuringAndRelatedCostImpactedEmployeesTermForCashPaymentsAndBenefits_41f10245-6444-4b1d-8141-15de8a19afdd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectOnFutureEarningsAmount_fa8cd9ff-e170-4f55-b2d8-4ff17553a3bf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EffectOnFutureEarningsAmount"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_b9acfb65-afd6-42f2-858c-dfe8359686ba" xlink:to="loc_us-gaap_EffectOnFutureEarningsAmount_fa8cd9ff-e170-4f55-b2d8-4ff17553a3bf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringAndRelatedCostExpectedCostRemaining1_792f2ada-26e0-43bd-ad49-f85515c67dab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestructuringAndRelatedCostExpectedCostRemaining1"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_b9acfb65-afd6-42f2-858c-dfe8359686ba" xlink:to="loc_us-gaap_RestructuringAndRelatedCostExpectedCostRemaining1_792f2ada-26e0-43bd-ad49-f85515c67dab" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNumberOfDefendants_e7c0a193-159c-41d1-a162-09ebd3edd1ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNumberOfDefendants"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_b9acfb65-afd6-42f2-858c-dfe8359686ba" xlink:to="loc_us-gaap_LossContingencyNumberOfDefendants_e7c0a193-159c-41d1-a162-09ebd3edd1ee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
</link:linkbase>
