content: <?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>0001973848</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0001962918</issuerCik>
        <issuerName>ACELYRIN, INC.</issuerName>
        <secFileNumber>001-41696</secFileNumber>
        <issuerAddress>
          <com:street1>4149 Liberty Canyon Road</com:street1>
          <com:city>Agoura Hills</com:city>
          <com:stateOrCountry>CA</com:stateOrCountry>
          <com:zipCode>91301</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>805-730-0360</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Peloso Paul</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Former Affiliate</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>Morgan Stanley Smith Barney LLC</name>
          <address>
            <com:street1>1 New York Plaza</com:street1>
            <com:street2>8th Floor</com:street2>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10004</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>56129</noOfUnitsSold>
        <aggregateMarketValue>470361.00</aggregateMarketValue>
        <noOfUnitsOutstanding>97339494</noOfUnitsOutstanding>
        <approxSaleDate>03/20/2024</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>03/20/2024</acquiredDate>
        <natureOfAcquisitionTransaction>Cashless Exercise of Employee Stock Options under an S-8 Registered Plan</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>56129</amountOfSecuritiesAcquired>
        <paymentDate>03/20/2024</paymentDate>
        <natureOfPayment>Cash</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <remarks>This Form 144 is being filed for the cashless exercise of options and subsequent sales of the underlying shares commencing on 03/20/2024.</remarks>
      <noticeSignature>
        <noticeDate>03/20/2024</noticeDate>
        <signature>/s/ Paul Peloso</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 2975}]
text: 144
  0001973848
  XXXXXXXX
  LIVE
  0001962918
  ACELYRIN, INC.
  001-41696
  4149 Liberty Canyon Road
  Agoura Hills
  CA
  91301
  805-730-0360
  Peloso Paul
  Former Affiliate
  Common
  Morgan Stanley Smith Barney LLC
  1 New York Plaza
  8th Floor
  New York
  NY
  10004
  56129
  470361.00
  97339494
  03/20/2024
  NASDAQ
  Common
  03/20/2024
  Cashless Exercise of Employee Stock Options under an S-8 Registered Plan
  Issuer
  N
  56129
  03/20/2024
  Cash
  Y
  This Form 144 is being filed for the cashless exercise of options and subsequent sales of the underlying shares commencing on 03/20/2024.
  03/20/2024
  /s/ Paul Peloso