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>0001200401</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0001018963</issuerCik>
        <issuerName>ATI INC</issuerName>
        <secFileNumber>001-12001</secFileNumber>
        <issuerAddress>
          <com:street1>2021 MCKINNEY AVENUE</com:street1>
          <com:city>DALLAS</com:city>
          <com:stateOrCountry>TX</com:stateOrCountry>
          <com:zipCode>75201</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>4123942800</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>DIGGS JAMES C</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Director</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>Fidelity Brokerage Services LLC</name>
          <address>
            <com:street1>900 Salem Street</com:street1>
            <com:city>Smithfield</com:city>
            <com:stateOrCountry>RI</com:stateOrCountry>
            <com:zipCode>02917</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>2674</noOfUnitsSold>
        <aggregateMarketValue>120062.60</aggregateMarketValue>
        <noOfUnitsOutstanding>128584727</noOfUnitsOutstanding>
        <approxSaleDate>09/08/2023</approxSaleDate>
        <securitiesExchangeName>NYSE</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>05/07/2013</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>5</amountOfSecuritiesAcquired>
        <paymentDate>05/07/2013</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>05/10/2019</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>575</amountOfSecuritiesAcquired>
        <paymentDate>05/10/2019</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <securitiesToBeSold>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <acquiredDate>05/25/2022</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Vesting</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>2094</amountOfSecuritiesAcquired>
        <paymentDate>05/25/2022</paymentDate>
        <natureOfPayment>Compensation</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>09/08/2023</noticeDate>
        <planAdoptionDates>
          <planAdoptionDate>06/09/2023</planAdoptionDate>
        </planAdoptionDates>
        <signature>/s/Wade Moss, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for James C Diggs</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 3990}]
text: 144
  0001200401
  XXXXXXXX
  LIVE
  0001018963
  ATI INC
  001-12001
  2021 MCKINNEY AVENUE
  DALLAS
  TX
  75201
  4123942800
  DIGGS JAMES C
  Director
  Common
  Fidelity Brokerage Services LLC
  900 Salem Street
  Smithfield
  RI
  02917
  2674
  120062.60
  128584727
  09/08/2023
  NYSE
  Common
  05/07/2013
  Restricted Stock Vesting
  Issuer
  N
  5
  05/07/2013
  Compensation
  Common
  05/10/2019
  Restricted Stock Vesting
  Issuer
  N
  575
  05/10/2019
  Compensation
  Common
  05/25/2022
  Restricted Stock Vesting
  Issuer
  N
  2094
  05/25/2022
  Compensation
  Y
  09/08/2023
  06/09/2023
  /s/Wade Moss, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for James C Diggs