-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001005757-05-000026.txt : 20050113
<SEC-HEADER>0001005757-05-000026.hdr.sgml : 20050113
<ACCEPTANCE-DATETIME>20050113152650
ACCESSION NUMBER:		0001005757-05-000026
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20050111
FILED AS OF DATE:		20050113
DATE AS OF CHANGE:		20050113

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Scott Robert M
		CENTRAL INDEX KEY:			0001312383

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-27512
		FILM NUMBER:		05528100

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		303-796-2850

	MAIL ADDRESS:	
		STREET 1:		7887 E. BELLEVIEW AVE.
		STREET 2:		SUITE 1000
		CITY:			ENGLEWOOD
		STATE:			CO
		ZIP:			80111

	FORMER NAME:	
		FORMER CONFORMED NAME:	Scott Robert Mike
		DATE OF NAME CHANGE:	20041222

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:		7887 EAST BELLEVIEW AVE
		STREET 2:		SUITE 1000
		CITY:			ENGLEWOOD
		STATE:			CO
		ZIP:			80111
		BUSINESS PHONE:		3037962850

	MAIL ADDRESS:	
		STREET 1:		7887 E. BELLVIEW AVE.
		STREET 2:		SUITE 1000
		CITY:			ENGLEWOOD
		STATE:			CO
		ZIP:			80111
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c0001312383d20050113f4f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-01-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001312383</rptOwnerCik>
            <rptOwnerName>Scott Robert M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7887 E. BELLEVIEW AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1000</rptOwnerStreet2>
            <rptOwnerCity>ENGLEWOOD</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80111</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-01-11</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2005-01-11</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>25000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>45840</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2073</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Robert Michael Scott Living Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Options (Right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>9.11</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-03-05</value>
            </exerciseDate>
            <expirationDate>
                <value>2013-03-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>11250</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11250</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares reported in Table I are exercisable in 4 equal annual installments.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>ROBERT M SCOTT</signatureName>
        <signatureDate>2005-01-13</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----