<SUBMISSION>
<ACCESSION-NUMBER>0001206774-04-000175
<TYPE>5/A
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20010930
<FILING-DATE>20040315
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>AMERICAN PACIFIC CORP
<CIK>0000350832
<ASSIGNED-SIC>2810
<IRS-NUMBER>596490478
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>0930
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>3770 HOWARD HUGHES PKWY STE 300
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89109
<PHONE>7027352200
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>3770 HOWARD HUGHES PKWY STE 300
<STREET2>3770 HOWARD HUGHES PKWY STE 300
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89109
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>GIBSON FRED D JR
<CIK>0001267599
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>5/A
<ACT>34
<FILE-NUMBER>001-08137
<FILM-NUMBER>04670752
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>3770 HOWARD HUGHES PARKWAY
<STREET2>SUITE 300
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89109
<PHONE>702-735-2200
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>3770 HOWARD HUGHES PARKWAY
<STREET2>STE 300
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89109
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>5/A
<SEQUENCE>1
<FILENAME>ap71149_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>5/A</documentType>

    <periodOfReport>2001-09-30</periodOfReport>

    <dateOfOriginalSubmission>2001-11-12</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000350832</issuerCik>
        <issuerName>AMERICAN PACIFIC CORP</issuerName>
        <issuerTradingSymbol>APFC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001267599</rptOwnerCik>
            <rptOwnerName>GIBSON FRED D JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3770 HOWARD HUGHES PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 300</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>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>392012</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Options to Purchase</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.375</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>1996-12-30</value>
            </exerciseDate>
            <expirationDate>
                <value>2001-12-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>30250</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30250</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Options to Purchase</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.375</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>1997-12-30</value>
            </exerciseDate>
            <expirationDate>
                <value>2002-12-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>30250</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>30250</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Options to Purchase</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>7.781</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>1999-09-14</value>
            </exerciseDate>
            <expirationDate>
                <value>2004-09-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Options to Purchase</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>7.781</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2000-09-14</value>
            </exerciseDate>
            <expirationDate>
                <value>2005-09-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeTransaction>
            <securityTitle>
                <value>Options to Purchase</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.87</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2001-04-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2001-04-24</value>
            </exerciseDate>
            <expirationDate>
                <value>2011-04-24</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Options to Purchase</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.87</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2001-04-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2002-04-24</value>
            </exerciseDate>
            <expirationDate>
                <value>2011-04-24</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2500</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This Form 4 is being amended to correct a clerical error in entering the amount of securities owned as reflected in Column 5, Table I.</footnote>
        <footnote id="F2">Omitted in accordance with General Instructions for Form 4, Rule 4(c)(iii).</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ David N. Keys</signatureName>
        <signatureDate>2004-03-10</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
