<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
  <headerData>
    <submissionType>144</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <cik>0001456750</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <issuerInfo>
      <issuerCik>0001042074</issuerCik>
      <issuerName>CymaBay Therapeutics, Inc.</issuerName>
      <secFileNumber>001-36500</secFileNumber>
      <issuerAddress>
        <com:street1>7575 GATEWAY BOULEVARD</com:street1>
        <com:street2>SUITE 110</com:street2>
        <com:city>NEWARK</com:city>
        <com:stateOrCountry>CA</com:stateOrCountry>
        <com:zipCode>94560</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>510-293-8800</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>KIM DENNIS D</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Officer</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>ETRADE FINANCIAL CORPORATION</name>
        <address>
          <com:street1>3 EDISON DRIVE</com:street1>
          <com:city>ALPHARETTA</com:city>
          <com:stateOrCountry>GA</com:stateOrCountry>
          <com:zipCode>30005</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>139344</noOfUnitsSold>
      <aggregateMarketValue>1532784.00</aggregateMarketValue>
      <noOfUnitsOutstanding>97500000</noOfUnitsOutstanding>
      <approxSaleDate>06/30/2023</approxSaleDate>
      <securitiesExchangeName>NASDAQ</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <acquiredDate>06/30/2023</acquiredDate>
      <natureOfAcquisitionTransaction>STOCK OPTION EXERCISE</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>ISSUER</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>139344</amountOfSecuritiesAcquired>
      <paymentDate>06/30/2023</paymentDate>
      <natureOfPayment>COMPENSATION</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>DENNIS KIM</name>
        <address>
          <com:street1>7575 GATEWAY BLVD, SUITE 110,</com:street1>
          <com:city>NEWARK</com:city>
          <com:stateOrCountry>CA</com:stateOrCountry>
          <com:zipCode>94560</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>STOCK OPTION EXERCISE</securitiesClassTitle>
      <saleDate>04/17/2023</saleDate>
      <amountOfSecuritiesSold>112219</amountOfSecuritiesSold>
      <grossProceeds>1070534.47</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>DENNIS KIM</name>
        <address>
          <com:street1>7575 GATEWAY BLVD, SUITE 110</com:street1>
          <com:city>NEWARK</com:city>
          <com:stateOrCountry>CA</com:stateOrCountry>
          <com:zipCode>94560</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>STOCK OPTION EXERCISE</securitiesClassTitle>
      <saleDate>04/13/2023</saleDate>
      <amountOfSecuritiesSold>7781</amountOfSecuritiesSold>
      <grossProceeds>69880.22</grossProceeds>
    </securitiesSoldInPast3Months>
    <noticeSignature>
      <noticeDate>06/30/2023</noticeDate>
      <signature>/s/ Dennis Kim</signature>
    </noticeSignature>
  </formData>
</edgarSubmission>
