<?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>0001053645</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <issuerInfo>
      <issuerCik>0000356037</issuerCik>
      <issuerName>csp inc</issuerName>
      <secFileNumber>000-10843</secFileNumber>
      <issuerAddress>
        <com:street1>175 CABOT ST</com:street1>
        <com:street2>suite 210</com:street2>
        <com:city>LOWELL</com:city>
        <com:stateOrCountry>MA</com:stateOrCountry>
        <com:zipCode>01854</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>9789545038</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>JAMES C SHELTON</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Director</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>MERRILL LYNCH</name>
        <address>
          <com:street1>1 TOWN CENTER RD</com:street1>
          <com:city>BOCA RATON</com:city>
          <com:stateOrCountry>FL</com:stateOrCountry>
          <com:zipCode>33486</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>20000</noOfUnitsSold>
      <aggregateMarketValue>346200.00</aggregateMarketValue>
      <noOfUnitsOutstanding>9880413</noOfUnitsOutstanding>
      <approxSaleDate>03/19/2025</approxSaleDate>
      <securitiesExchangeName>NASDAQ</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <acquiredDate>01/01/2004</acquiredDate>
      <natureOfAcquisitionTransaction>IN LIEU OF SERVICES</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>CSP INC</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>20000</amountOfSecuritiesAcquired>
      <paymentDate>01/01/2004</paymentDate>
      <natureOfPayment>IN LIEU OF SERVICES</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>MERRILL LYNCH</name>
        <address>
          <com:street1>1 TOWN CENTER RD</com:street1>
          <com:city>BOCA RATON </com:city>
          <com:stateOrCountry>FL</com:stateOrCountry>
          <com:zipCode>33486</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <saleDate>02/13/2025</saleDate>
      <amountOfSecuritiesSold>1500</amountOfSecuritiesSold>
      <grossProceeds>28399.64</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>MERRILL LYNCH</name>
        <address>
          <com:street1>1 TOWN CENTER RD</com:street1>
          <com:city>BOCA RATON </com:city>
          <com:stateOrCountry>FL</com:stateOrCountry>
          <com:zipCode>33486</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <saleDate>02/13/2025</saleDate>
      <amountOfSecuritiesSold>1500</amountOfSecuritiesSold>
      <grossProceeds>28259.46</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>MERRILL LYNCH</name>
        <address>
          <com:street1>1 TOWN CENTER RD</com:street1>
          <com:city>BOCA RATON</com:city>
          <com:stateOrCountry>FL</com:stateOrCountry>
          <com:zipCode>33486</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <saleDate>02/14/2025</saleDate>
      <amountOfSecuritiesSold>3000</amountOfSecuritiesSold>
      <grossProceeds>56770.11</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>MERRILL LYNCH</name>
        <address>
          <com:street1>1 TOWN CENTER RD</com:street1>
          <com:city>BOCA RATON</com:city>
          <com:stateOrCountry>FL</com:stateOrCountry>
          <com:zipCode>33486</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <saleDate>02/18/2025</saleDate>
      <amountOfSecuritiesSold>1500</amountOfSecuritiesSold>
      <grossProceeds>29710.70</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>MERRILL LYNCH</name>
        <address>
          <com:street1>1 TOWN CENTER RD</com:street1>
          <com:city>BOCA RATON</com:city>
          <com:stateOrCountry>FL</com:stateOrCountry>
          <com:zipCode>33486</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <saleDate>02/19/2025</saleDate>
      <amountOfSecuritiesSold>1000</amountOfSecuritiesSold>
      <grossProceeds>18104.14</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>MERRILL LYNCH</name>
        <address>
          <com:street1>1 TOWN CENTER RD</com:street1>
          <com:city>BOCA RATON </com:city>
          <com:stateOrCountry>FL</com:stateOrCountry>
          <com:zipCode>33486</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>COMMON</securitiesClassTitle>
      <saleDate>02/25/2025</saleDate>
      <amountOfSecuritiesSold>1326</amountOfSecuritiesSold>
      <grossProceeds>22081.64</grossProceeds>
    </securitiesSoldInPast3Months>
    <noticeSignature>
      <noticeDate>03/19/2025</noticeDate>
      <signature>JAMES SHELTON</signature>
    </noticeSignature>
  </formData>
</edgarSubmission>
