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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001127602-09-010686.txt : 20090505
<SEC-HEADER>0001127602-09-010686.hdr.sgml : 20090505
<ACCEPTANCE-DATETIME>20090505201943
ACCESSION NUMBER:		0001127602-09-010686
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090501
FILED AS OF DATE:		20090505
DATE AS OF CHANGE:		20090505

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			NEILSEN RAY H
		CENTRAL INDEX KEY:			0001382070

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-22494
		FILM NUMBER:		09799192

	MAIL ADDRESS:	
		STREET 1:		C/O AMERISTAR CASINOS, INC.
		STREET 2:		3773 HOWARD HUGHES PARKWAY, SUITE 490S
		CITY:			LAS VEGAS
		STATE:			NV
		ZIP:			89169

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:			89169
		BUSINESS PHONE:		7025677000

	MAIL ADDRESS:	
		STREET 1:		3773 HOWARD HUGHES PKWY
		STREET 2:		SUITE 490 SOUTH
		CITY:			LAS VEGAS
		STATE:			NV
		ZIP:			89169
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-05-01</periodOfReport>

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

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            <rptOwnerName>NEILSEN RAY H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3773 HOWARD HUGHES PKWY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 490S</rptOwnerStreet2>
            <rptOwnerCity>LAS VEGAS</rptOwnerCity>
            <rptOwnerState>NV</rptOwnerState>
            <rptOwnerZipCode>89169</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <officerTitle>Chairman of the Board</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
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            <transactionCoding>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
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                <transactionPricePerShare>
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                <value>Common Stock</value>
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                <transactionFormType>4</transactionFormType>
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                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>15509</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.92</value>
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                <transactionAcquiredDisposedCode>
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            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>174699</value>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
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            <transactionDate>
                <value>2009-05-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
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                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12800</value>
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                <transactionPricePerShare>
                    <value>19.93</value>
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                <transactionAcquiredDisposedCode>
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            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>161899</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
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                </transactionShares>
                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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                <sharesOwnedFollowingTransaction>
                    <value>144430</value>
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                <directOrIndirectOwnership>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
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                </transactionShares>
                <transactionPricePerShare>
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                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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        <nonDerivativeTransaction>
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                <transactionFormType>4</transactionFormType>
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                <transactionShares>
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                </transactionShares>
                <transactionPricePerShare>
                    <value>20.10</value>
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                <transactionAcquiredDisposedCode>
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                </transactionAcquiredDisposedCode>
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                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
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            <conversionOrExercisePrice>
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            <transactionDate>
                <value>2009-05-01</value>
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                <transactionFormType>4</transactionFormType>
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            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>9384</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2003-12-19</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-12-20</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
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                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9384</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>11.5275</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-05-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16125</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-12-10</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-12-11</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>16125</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1815</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>11.5275</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-05-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1815</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-12-10</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-12-11</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1815</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Balance includes restricted stock units, each of which represents a right to receive one share of common stock in the future.</footnote>
        <footnote id="F2">Options vested in five equal annual installments commencing on December 19, 2003.</footnote>
        <footnote id="F3">Options vested in five equal annual installments commencing on December 10, 2004.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Peter C. Walsh, Attorney-in-Fact</signatureName>
        <signatureDate>2009-05-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----