<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2006-06-20</periodOfReport>

    <dateOfOriginalSubmission>2006-06-22</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001032220</issuerCik>
        <issuerName>MAXIMUS INC</issuerName>
        <issuerTradingSymbol>MMS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001254635</rptOwnerCik>
            <rptOwnerName>MONTONI RICHARD A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MAXIMUS INC</rptOwnerStreet1>
            <rptOwnerStreet2>11419 SUNSET HILLS RD</rptOwnerStreet2>
            <rptOwnerCity>RESTON</rptOwnerCity>
            <rptOwnerState>VA</rptOwnerState>
            <rptOwnerZipCode>20190</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO and Director</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units (RSU)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>29.66</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-06-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>18079</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>18079</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>133806</value>
                    <footnoteId id="F5"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>29.66</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-06-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>225500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2007-06-20</value>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-06-20</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>225500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>225500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each RSU represents a contingent right to receive one share of common stock.</footnote>
        <footnote id="F2">These awards are being issued pursuant to the Executive Employment, Non-Compete and Confidentiality Agreement between Mr. Montoni and MAXIMUS dated April 21,2006, to replace awards that Mr. Montoni forfeited or would forfeit if not exercised prior to June 30,2006 as a result of the termination of his employment with the company on March 31,2006.</footnote>
        <footnote id="F3">Restricted stock units vest based on the following schedule:

Shares   Vest Date
3,792     03/31/2007
3,791     03/31/2008
3,208     03/31/2009
3,207     03/31/2010
2,582     03/31/2011
1,499     03/31/2012</footnote>
        <footnote id="F4">Expiration date not applicable to RSU's.</footnote>
        <footnote id="F5">Of this amount, 130,579 shares are restricted and subject to future vesting pursuant to the terms of the grant of restricted stock previously made by the issuer to the reporting person.  The reporting person does not have voting or dispositive power over these shares of restricted stock.</footnote>
        <footnote id="F6">Options vest as follows:

Shares   Vest Date
56,375    06/20/2007
56,375    06/20/2008
56,375    06/20/2009
56,375    06/20/2010</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>David R. Francis: As Attorney-In-Fact for Richard A. Montoni</signatureName>
        <signatureDate>2006-06-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
