<SUBMISSION>
<ACCESSION-NUMBER>0001181431-06-056639
<TYPE>4/A
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20060929
<FILING-DATE>20061004
<DATE-OF-FILING-DATE-CHANGE>20061004
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>Western Union CO
<CIK>0001365135
<ASSIGNED-SIC>7389
<IRS-NUMBER>204531180
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>100 SUMMIT AVENUE
<CITY>MONTVALE
<STATE>NJ
<ZIP>07645
<PHONE>(201) 263-5949
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>100 SUMMIT AVENUE
<CITY>MONTVALE
<STATE>NJ
<ZIP>07645
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>THOMAS WILLIAM DAVID
<CIK>0001223474
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4/A
<ACT>34
<FILE-NUMBER>001-32903
<FILM-NUMBER>061126737
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>C/O FIRST DATA CORP
<STREET2>10825 OLD MILL ROAD M-10
<CITY>OMAHA
<STATE>NE
<ZIP>68154
<PHONE>402-951-7008
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>FIRST DATA CORPORATION
<STREET2>10825 FARNAM DR, C-12
<CITY>OMAHA
<STATE>NE
<ZIP>68154
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>rrd132505.xml
<DESCRIPTION>FORM 4/A
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2006-09-29</periodOfReport>

    <dateOfOriginalSubmission>2006-10-03</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001365135</issuerCik>
        <issuerName>Western Union CO</issuerName>
        <issuerTradingSymbol>WU</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001223474</rptOwnerCik>
            <rptOwnerName>THOMAS WILLIAM DAVID</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>12500 EAST BELFORD AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ENGLEWOOD</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80112</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP &amp; Pres. of the Americas</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>40426</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On October 3, 2006, the reporting person filed a Form 4 that inadvertently omitted from his holdings 7,267 shares that were acquired in connection with with the distribution by First Data Corporation of shares of common stock of The Western Union Company.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Sarah J. Kilgore as Attorney-in-Fact for William D. Thomas</signatureName>
        <signatureDate>2006-10-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
