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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 70qCL4KQM7udqwVh/A6NNQ==

<SEC-DOCUMENT>0000878897-04-000042.txt : 20041004
<SEC-HEADER>0000878897-04-000042.hdr.sgml : 20041004
<ACCEPTANCE-DATETIME>20041004143528
ACCESSION NUMBER:		0000878897-04-000042
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040930
FILED AS OF DATE:		20041004
DATE AS OF CHANGE:		20041004

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AMERICAN MEDICAL SECURITY GROUP INC
		CENTRAL INDEX KEY:			0000878897
		STANDARD INDUSTRIAL CLASSIFICATION:	HOSPITAL & MEDICAL SERVICE PLANS [6324]
		IRS NUMBER:				391431799
		STATE OF INCORPORATION:			WI
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		3100 AMS BLVD
		CITY:			GREEN BAY
		STATE:			WI
		ZIP:			54313
		BUSINESS PHONE:		9206611111

	MAIL ADDRESS:	
		STREET 1:		3100 AMS BLVD
		CITY:			GREEN BAY
		STATE:			WI
		ZIP:			54313

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	UNITED WISCONSIN SERVICES INC /WI
		DATE OF NAME CHANGE:	19930328

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCHREYER HT RICHARD
		CENTRAL INDEX KEY:			0001181983
		STATE OF INCORPORATION:			VA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13154
		FILM NUMBER:		041061921

	BUSINESS ADDRESS:	
		STREET 1:		C/O AMERICAN MECICAL SECURITY GROUP INC
		STREET 2:		3100 AMS BLVD
		CITY:			GREEN BAY
		STATE:			WI
		ZIP:			54313
		BUSINESS PHONE:		9206611111

	MAIL ADDRESS:	
		STREET 1:		C/O AMERICAN MECICAL SECURITY GROUP INC
		STREET 2:		3100 AMS BLVD
		CITY:			GREEN BAY
		STATE:			WI
		ZIP:			54313
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-09-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000878897</issuerCik>
        <issuerName>AMERICAN MEDICAL SECURITY GROUP INC</issuerName>
        <issuerTradingSymbol>AMZ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001181983</rptOwnerCik>
            <rptOwnerName>SCHREYER HT RICHARD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AMERICAN MECICAL SECURITY GROUP INC</rptOwnerStreet1>
            <rptOwnerStreet2>3100 AMS BLVD</rptOwnerStreet2>
            <rptOwnerCity>GREEN BAY</rptOwnerCity>
            <rptOwnerState>WI</rptOwnerState>
            <rptOwnerZipCode>54313</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>2004-09-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>155.32</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>31.99</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9481.6</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>/s/ H.T. Richard Schreyer</signatureName>
        <signatureDate>2004-10-03</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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