<SUBMISSION>
<ACCESSION-NUMBER>0001005477-03-004524
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20031020
<FILING-DATE>20031124
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>UNITED SECURITY BANCSHARES
<CIK>0001137547
<ASSIGNED-SIC>6021
<IRS-NUMBER>912112732
<STATE-OF-INCORPORATION>CA
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>1525 E SHAW AVENUE
<CITY>FRESO
<STATE>CA
<ZIP>93710
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>1525 E SHAW AVENUE
<CITY>FRESNO
<STATE>CA
<ZIP>93710
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>THOMASON AUDRY BOBBI
<CIK>0001145945
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-32897
<FILM-NUMBER>031021638
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>1525 E SHAW AVE
<CITY>FRESNO
<STATE>CA
<ZIP>93710
<PHONE>5592484943
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>1525 E SHAW AVE
<CITY>FRESNO
<STATE>CA
<ZIP>93710
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar123.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
    <periodOfReport>2003-10-20</periodOfReport>
    <notSubjectToSection16>1</notSubjectToSection16>
    <issuer>
        <issuerCik>0001137547</issuerCik>
        <issuerName>UNITED SECURITY BANCSHARES</issuerName>
        <issuerTradingSymbol>UBFO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>

        <reportingOwnerId>
            <rptOwnerCik>0001145945</rptOwnerCik>
            <rptOwnerName>THOMASON AUDRY BOBBI</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
        <isDirector>1</isDirector>
        <isOfficer>0</isOfficer>
        <isTenPercentOwner>0</isTenPercentOwner>
        <isOther>0</isOther>
    </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>

        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>

        <transactionDate>
            <value>2003-10-20</value>
        </transactionDate>

        <deemedExecutionDate>
            <value>2003-10-20</value>
        </deemedExecutionDate>
    <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>P</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
    </transactionCoding>
        <transactionAmounts>

            <transactionShares>
                <value>1070.293</value>
            </transactionShares>

            <transactionPricePerShare>
                <value>25.00</value>
            </transactionPricePerShare>

            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>

            <sharesOwnedFollowingTransaction>
                <value>340368</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>

            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
        </nonDerivativeTransaction>

        <nonDerivativeTransaction>

        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>

        <transactionDate>
            <value>2003-11-14</value>
        </transactionDate>

        <deemedExecutionDate>
            <value>2003-11-14</value>
        </deemedExecutionDate>
    <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>P</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
    </transactionCoding>
        <transactionAmounts>

            <transactionShares>
                <value>496.224</value>
            </transactionShares>

            <transactionPricePerShare>
                <value>26.35</value>
            </transactionPricePerShare>

            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>

            <sharesOwnedFollowingTransaction>
                <value>340864</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>

            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
        </nonDerivativeTransaction>

        <nonDerivativeTransaction>

        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>

        <transactionDate>
            <value>2003-11-24</value>
        </transactionDate>

        <deemedExecutionDate>
            <value>2003-11-24</value>
        </deemedExecutionDate>
    <transactionCoding>
        <transactionFormType>4</transactionFormType>
        <transactionCode>P</transactionCode>
        <equitySwapInvolved>0</equitySwapInvolved>
    </transactionCoding>
        <transactionAmounts>

            <transactionShares>
                <value>265</value>
            </transactionShares>

            <transactionPricePerShare>
                <value>26.35</value>
            </transactionPricePerShare>

            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>

            <sharesOwnedFollowingTransaction>
                <value>341129</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>

            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
        </nonDerivativeTransaction>

    </nonDerivativeTable>
<remarks>Indirect shares = 19,488.</remarks>

    <ownerSignature>
        <signatureName>/s/ Audry Bobbi Thomason</signatureName>
        <signatureDate>2003-11-24</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
