-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 Se9d8GRgu1xLbYz7Vf/zKEoSu0Xgxw3TdWm3+yrSMcwlzu79YEgyf9b1+W/2FA++
 0960CUqE9IpbdGQOG1hC8A==

<SEC-DOCUMENT>0001104659-04-018577.txt : 20040630
<SEC-HEADER>0001104659-04-018577.hdr.sgml : 20040630
<ACCEPTANCE-DATETIME>20040630154327
ACCESSION NUMBER:		0001104659-04-018577
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040630
FILED AS OF DATE:		20040630

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			VAN DYKE WILLIAM G
		CENTRAL INDEX KEY:			0001190816

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10582
		FILM NUMBER:		04891380

	MAIL ADDRESS:	
		STREET 1:		P.O. BOX 1441
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55440-1441

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ALLIANT TECHSYSTEMS INC
		CENTRAL INDEX KEY:			0000866121
		STANDARD INDUSTRIAL CLASSIFICATION:	GUIDED MISSILES & SPACE VEHICLES & PARTS [3760]
		IRS NUMBER:				411672694
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		5050 LINCOLN DRIVE
		CITY:			EDINA
		STATE:			MN
		ZIP:			55436-1097
		BUSINESS PHONE:		9523513000

	MAIL ADDRESS:	
		STREET 1:		5050 LINCOLN DRIVE
		CITY:			EDINA
		STATE:			MN
		ZIP:			55436-1097
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>a4.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-06-30</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000866121</issuerCik>
        <issuerName>ALLIANT TECHSYSTEMS INC</issuerName>
        <issuerTradingSymbol>ATK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001190816</rptOwnerCik>
            <rptOwnerName>VAN DYKE WILLIAM G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ALLIANT TECHYSTEMS</rptOwnerStreet1>
            <rptOwnerStreet2>5050 LINCOLN DRIVE</rptOwnerStreet2>
            <rptOwnerCity>EDINA</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55436-1097</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-06-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>163.7119</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>62.61</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>163.7119</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1272.4057</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares of Phantom Stock are represented by Share Units accrued under the Issuer's Deferred Fee Plan for Non-Employee Directors and are to be settled 100% in cash in five annual installments starting on the first business day of the year after the reporting person ceases to be a director of the Issuer.</footnote>
        <footnote id="F2">Converts to common stock 1-for-1.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/William G. Van Dyke</signatureName>
        <signatureDate>2004-06-30</signatureDate>
    </ownerSignature>
</ownershipDocument>

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