<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:ns2="http://www.sec.gov/edgar/common">
    <headerData>
        <submissionType>144</submissionType>
        <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001998333</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0001990354</issuerCik>
            <issuerName>WAYSTAR HOLDING CORP</issuerName>
            <secFileNumber>001-42125</secFileNumber>
            <issuerAddress>
                <ns2:street1>1550 Digital Drive, #300</ns2:street1>
                <ns2:city>Lehi</ns2:city>
                <ns2:stateOrCountry>UT</ns2:stateOrCountry>
                <ns2:zipCode>84043</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>8444929782</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>CHRISTOPHER SCHREMSER</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Officer</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>Morgan Stanley Smith Barney LLC Executive Financial Services</name>
                <address>
                    <ns2:street1>1 New York Plaza</ns2:street1>
                    <ns2:street2>8th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>25869</noOfUnitsSold>
            <aggregateMarketValue>1053385.68</aggregateMarketValue>
            <noOfUnitsOutstanding>173018999</noOfUnitsOutstanding>
            <approxSaleDate>06/10/2025</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>06/10/2025</acquiredDate>
            <natureOfAcquisitionTransaction>Exercise of Stock Options</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>25869</amountOfSecuritiesAcquired>
            <paymentDate>06/10/2025</paymentDate>
            <natureOfPayment>Cash</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for CHRISTOPHER SCHREMSER</name>
                <address>
                    <ns2:street1>1550 Digital Drive, #300</ns2:street1>
                    <ns2:city>Lehi</ns2:city>
                    <ns2:stateOrCountry>UT</ns2:stateOrCountry>
                    <ns2:zipCode>84043</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>05/09/2025</saleDate>
            <amountOfSecuritiesSold>8623</amountOfSecuritiesSold>
            <grossProceeds>346352.28</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for CHRISTOPHER SCHREMSER</name>
                <address>
                    <ns2:street1>1550 Digital Drive, #300</ns2:street1>
                    <ns2:city>Lehi</ns2:city>
                    <ns2:stateOrCountry>UT</ns2:stateOrCountry>
                    <ns2:zipCode>84043</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>04/10/2025</saleDate>
            <amountOfSecuritiesSold>8623</amountOfSecuritiesSold>
            <grossProceeds>313546.08</grossProceeds>
        </securitiesSoldInPast3Months>
        <remarks>The securities to be sold were and will be received upon the exercise of stock options over the next three months. The dates of acquisition and payment were and will be the dates of exercise/sale.&#13;
</remarks>
        <noticeSignature>
            <noticeDate>06/10/2025</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>12/06/2024</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ Christopher Schremser</signature>
        </noticeSignature>
    </formData>
</edgarSubmission>
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144
0001998333
XXXXXXXX
LIVE
0001990354
WAYSTAR HOLDING CORP
001-42125
1550 Digital Drive, #300
Lehi
UT
84043
8444929782
CHRISTOPHER SCHREMSER
Officer
Common
Morgan Stanley Smith Barney LLC Executive Financial Services
1 New York Plaza
8th Floor
New York
NY
10004
25869
1053385.68
173018999
06/10/2025
NASDAQ
Common
06/10/2025
Exercise of Stock Options
Issuer
N
25869
06/10/2025
Cash
N
10b5-1 Sales for CHRISTOPHER SCHREMSER
1550 Digital Drive, #300
Lehi
UT
84043
Common
05/09/2025
8623
346352.28
10b5-1 Sales for CHRISTOPHER SCHREMSER
1550 Digital Drive, #300
Lehi
UT
84043
Common
04/10/2025
8623
313546.08
The securities to be sold were and will be received upon the exercise of stock options over the next three months. The dates of acquisition and payment were and will be the dates of exercise/sale.
06/10/2025
12/06/2024
/s/ Christopher Schremser