<SEC-DOCUMENT>0001127602-21-025270.txt : 20210914
<SEC-HEADER>0001127602-21-025270.hdr.sgml : 20210914
<ACCEPTANCE-DATETIME>20210914184054
ACCESSION NUMBER:		0001127602-21-025270
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210910
FILED AS OF DATE:		20210914
DATE AS OF CHANGE:		20210914

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Tavares Silvio
		CENTRAL INDEX KEY:			0001685787

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-27512
		FILM NUMBER:		211253656

	MAIL ADDRESS:	
		STREET 1:		20 TIPTOE LANE
		CITY:			BURLINGAME
		STATE:			CA
		ZIP:			94010

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CSG SYSTEMS INTERNATIONAL INC
		CENTRAL INDEX KEY:			0001005757
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER PROCESSING & DATA PREPARATION [7374]
		IRS NUMBER:				470783182
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		6175 SOUTH WILLOW DRIVE
		CITY:			GREENWOOD VILLAGE
		STATE:			CO
		ZIP:			80111
		BUSINESS PHONE:		3037962850

	MAIL ADDRESS:	
		STREET 1:		6175 SOUTH WILLOW DRIVE
		CITY:			GREENWOOD VILLAGE
		STATE:			CO
		ZIP:			80111
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-09-10</periodOfReport>

    <issuer>
        <issuerCik>0001005757</issuerCik>
        <issuerName>CSG SYSTEMS INTERNATIONAL INC</issuerName>
        <issuerTradingSymbol>CSGS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001685787</rptOwnerCik>
            <rptOwnerName>Tavares Silvio</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>6175 SOUTH WILLOW DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWOOD VILLAGE</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-09-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3672</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7768</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares of restricted stock granted which will vest one day immediately preceding the first annual general meeting of the Company's stockholders occurring after the Award Date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Danelle K. Benker, attorney-in-fact for Silvio Tavares</signatureName>
        <signatureDate>2021-09-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
