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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Lf9K/pUSMb5fHcscW1J0PrWjH+k7WnJaiB3CTmXQBWCF4WAYWrHKWh9tl8WSgb3h
 QpR6BpSnLXMWsBa7qHvs7w==

<SEC-DOCUMENT>0001209828-04-000002.txt : 20040402
<SEC-HEADER>0001209828-04-000002.hdr.sgml : 20040402
<ACCEPTANCE-DATETIME>20040402160343
ACCESSION NUMBER:		0001209828-04-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040331
FILED AS OF DATE:		20040402

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AMERISTAR CASINOS INC
		CENTRAL INDEX KEY:			0000912145
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-MISCELLANEOUS AMUSEMENT & RECREATION [7990]
		IRS NUMBER:				880304799
		STATE OF INCORPORATION:			NV
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		3773 HOWARD HUGHES PKWY
		STREET 2:		SUITE 490 SOUTH
		CITY:			LAS VEGAS
		STATE:			NV
		ZIP:			89109
		BUSINESS PHONE:		7025677000

	MAIL ADDRESS:	
		STREET 1:		3773 HOWARD HUGHES PKWY
		STREET 2:		SUITE 490 SOUTH
		CITY:			LAS VEGAS
		STATE:			NV
		ZIP:			89109

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TURNER W BRUCE
		CENTRAL INDEX KEY:			0001209828

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22494
		FILM NUMBER:		04714059

	BUSINESS ADDRESS:	
		STREET 1:		AMERISTAR CASINOS
		STREET 2:		3773 HOWARD HUGHES PKWY SUITE490 S
		CITY:			LAS BVAGAS
		STATE:			NV
		ZIP:			89109
		BUSINESS PHONE:		7025677000

	MAIL ADDRESS:	
		STREET 1:		3773 HOWARD HUGHES PKWY
		STREET 2:		SUITE 490 SOUTH
		CITY:			LAS VAGAS
		STATE:			NV
		ZIP:			89109
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c0001209828d20040402f4f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-03-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000912145</issuerCik>
        <issuerName>AMERISTAR CASINOS INC</issuerName>
        <issuerTradingSymbol>ASCA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001209828</rptOwnerCik>
            <rptOwnerName>TURNER W BRUCE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3773 HOWARD HUGHES PKWY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 490S</rptOwnerStreet2>
            <rptOwnerCity>LAS VEGAS</rptOwnerCity>
            <rptOwnerState>NV</rptOwnerState>
            <rptOwnerZipCode>89109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-03-31</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>324</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.98</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2792</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Shares were issued pursuant to the Issuer's 2002 Non-Employee Directors' Stock Election Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Gregory H. Cooper,  Attorney-in-Fact</signatureName>
        <signatureDate>2004-04-02</signatureDate>
    </ownerSignature>
</ownershipDocument>

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