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        <submissionType>144</submissionType>
        <filerInfo>
            <filer>
                <filerCredentials>
                    <cik>0001227348</cik>
                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



        </filerInfo>
    </headerData>
    <formData>
        <issuerInfo>
            <issuerCik>0001288847</issuerCik>
            <issuerName>FIVE9, INC.</issuerName>
            <secFileNumber>001-36383</secFileNumber>
            <issuerAddress>
                <ns2:street1>3001 Bishop Drive</ns2:street1>
                <ns2:street2>Suite 350</ns2:street2>
                <ns2:city>San Ramon</ns2:city>
                <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                <ns2:zipCode>94583</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>(925) 201-2000</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>BARRY ZWARENSTEIN</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>38th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>6007</noOfUnitsSold>
            <aggregateMarketValue>426254.49</aggregateMarketValue>
            <noOfUnitsOutstanding>72212312</noOfUnitsOutstanding>
            <approxSaleDate>09/05/2023</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>09/03/2023</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted Stock Units Vested under Issuer S-8 Registered Plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>6007</amountOfSecuritiesAcquired>
            <paymentDate>09/03/2023</paymentDate>
            <natureOfPayment>Services Rendered</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>Barry Zwarenstein</name>
                <address>
                    <ns2:street1>3001 Bishop Drive</ns2:street1>
                    <ns2:street2>Suite 350</ns2:street2>
                    <ns2:city>San Ramon</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94583</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/15/2023</saleDate>
            <amountOfSecuritiesSold>2698</amountOfSecuritiesSold>
            <grossProceeds>192340.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>Barry Zwarenstein</name>
                <address>
                    <ns2:street1>3001 Bishop Drive</ns2:street1>
                    <ns2:street2>Suite 350</ns2:street2>
                    <ns2:city>San Ramon</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94583</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/15/2023</saleDate>
            <amountOfSecuritiesSold>3957</amountOfSecuritiesSold>
            <grossProceeds>277860.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>Barry Zwarenstein</name>
                <address>
                    <ns2:street1>3001 Bishop Drive</ns2:street1>
                    <ns2:street2>Suite 350</ns2:street2>
                    <ns2:city>San Ramon</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94583</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>08/15/2023</saleDate>
            <amountOfSecuritiesSold>3345</amountOfSecuritiesSold>
            <grossProceeds>231340.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>Barry Zwarenstein</name>
                <address>
                    <ns2:street1>3001 Bishop Drive</ns2:street1>
                    <ns2:street2>Suite 350</ns2:street2>
                    <ns2:city>San Ramon</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94583</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>07/13/2023</saleDate>
            <amountOfSecuritiesSold>400</amountOfSecuritiesSold>
            <grossProceeds>35440.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>Barry Zwarenstein</name>
                <address>
                    <ns2:street1>3001 Bishop Drive</ns2:street1>
                    <ns2:street2>Suite 350</ns2:street2>
                    <ns2:city>San Ramon</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94583</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>07/13/2023</saleDate>
            <amountOfSecuritiesSold>6800</amountOfSecuritiesSold>
            <grossProceeds>598808.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>Barry Zwarenstein</name>
                <address>
                    <ns2:street1>3001 Bishop Drive</ns2:street1>
                    <ns2:street2>Suite 350</ns2:street2>
                    <ns2:city>San Ramon</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94583</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>07/13/2023</saleDate>
            <amountOfSecuritiesSold>5300</amountOfSecuritiesSold>
            <grossProceeds>462001.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>Barry Zwarenstein</name>
                <address>
                    <ns2:street1>3001 Bishop Drive</ns2:street1>
                    <ns2:street2>Suite 350</ns2:street2>
                    <ns2:city>San Ramon</ns2:city>
                    <ns2:stateOrCountry>CA</ns2:stateOrCountry>
                    <ns2:zipCode>94583</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>06/09/2023</saleDate>
            <amountOfSecuritiesSold>10000</amountOfSecuritiesSold>
            <grossProceeds>750400.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>09/05/2023</noticeDate>
            <planAdoptionDates/>
            <signature>/s/ Barry Zwarenstein</signature>
        </noticeSignature>
    </formData>
</edgarSubmission>
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144
0001227348
XXXXXXXX
LIVE
0001288847
FIVE9, INC.
001-36383
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
(925) 201-2000
BARRY ZWARENSTEIN
Officer
Common
Morgan Stanley Smith Barney LLC Executive Financial Services
1 New York Plaza
38th Floor
New York
NY
10004
6007
426254.49
72212312
09/05/2023
NASDAQ
Common
09/03/2023
Restricted Stock Units Vested under Issuer S-8 Registered Plan
Issuer
N
6007
09/03/2023
Services Rendered
N
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
08/15/2023
2698
192340.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
08/15/2023
3957
277860.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
08/15/2023
3345
231340.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
07/13/2023
400
35440.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
07/13/2023
6800
598808.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
07/13/2023
5300
462001.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
06/09/2023
10000
750400.00
09/05/2023
/s/ Barry Zwarenstein