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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>7934</noOfUnitsSold>
            <aggregateMarketValue>551505.83</aggregateMarketValue>
            <noOfUnitsOutstanding>71176473</noOfUnitsOutstanding>
            <approxSaleDate>06/05/2023</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>06/05/2023</acquiredDate>
            <natureOfAcquisitionTransaction>Restricted Stock Units Vested under Issuer S-8 Registered Plan</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>7934</amountOfSecuritiesAcquired>
            <paymentDate>06/05/2023</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>05/22/2023</saleDate>
            <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
            <grossProceeds>162725.00</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>05/18/2023</saleDate>
            <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
            <grossProceeds>150050.00</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>05/17/2023</saleDate>
            <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
            <grossProceeds>137550.00</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>04/17/2023</saleDate>
            <amountOfSecuritiesSold>10000</amountOfSecuritiesSold>
            <grossProceeds>712314.00</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>03/31/2023</saleDate>
            <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
            <grossProceeds>175200.00</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>03/29/2023</saleDate>
            <amountOfSecuritiesSold>2500</amountOfSecuritiesSold>
            <grossProceeds>162650.00</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>03/15/2023</saleDate>
            <amountOfSecuritiesSold>5000</amountOfSecuritiesSold>
            <grossProceeds>309221.00</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>03/06/2023</saleDate>
            <amountOfSecuritiesSold>1992</amountOfSecuritiesSold>
            <grossProceeds>136780.00</grossProceeds>
        </securitiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>06/05/2023</noticeDate>
            <planAdoptionDates/>
            <signature>/s/ Barry Zwarenstein</signature>
        </noticeSignature>
    </formData>
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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
7934
551505.83
71176473
06/05/2023
NASDAQ
Common
06/05/2023
Restricted Stock Units Vested under Issuer S-8 Registered Plan
Issuer
N
7934
06/05/2023
Services Rendered
N
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
05/22/2023
2500
162725.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
05/18/2023
2500
150050.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
05/17/2023
2500
137550.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
04/17/2023
10000
712314.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
03/31/2023
2500
175200.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
03/29/2023
2500
162650.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
03/15/2023
5000
309221.00
Barry Zwarenstein
3001 Bishop Drive
Suite 350
San Ramon
CA
94583
Common
03/06/2023
1992
136780.00
06/05/2023
/s/ Barry Zwarenstein