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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-11-17</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000005272</issuerCik>
        <issuerName>AMERICAN INTERNATIONAL GROUP INC</issuerName>
        <issuerTradingSymbol>AIG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001340459</rptOwnerCik>
            <rptOwnerName>C V STARR &amp; CO INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>399 PARK AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>17TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-11-17</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4423116</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13425748</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8580850</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Variable Prepaid Forward Contract</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.00</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-11-17</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4423116</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>4423116</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On November 15, 2005, C. V. Starr &amp; Co., Inc. (&quot;CV Starr&quot;) entered into a variable prepaid forward sale contract (the &quot;CS Contract&quot;) for up to 4,423,116 shares (the &quot;Maximum Number&quot;) of American International Group, Inc. common stock (the &quot;Common Stock&quot;) pursuant to a letter agreement by and among CV Starr, Credit Suisse First Boston LLC and Credit Suisse First Boston Capital LLC (&quot;Credit Suisse&quot;). This Form 4 is being filed in connection with the settlement of the CS Contract.</footnote>
        <footnote id="F2">The CS Contract provided that the number of shares of Common Stock deliverable to Credit Suisse by CV Starr at settlement would be based upon the VWAP Price (as defined in the CS Contract) for each of the 10 Scheduled Trading Days (as defined in the CS Contract) prior to and including November 17, 2008 (the &quot;Valuation Dates&quot;) as follows: (a) if the VWAP Price (as defined in the CS Contract) per share of the Common Stock (the &quot;Settlement Price&quot;) were less than or equal to $65.85 (the &quot;Forward Floor Price&quot;), a delivery of 1/10 of the Maximum Number of shares of Common Stock, subject to rounding; -- CONTINUES ONTO THE NEXT FOOTNOTE</footnote>
        <footnote id="F3">CONTINUED FROM THE PREVIOUS FOOTNOTE -- (b) if the Settlement Price were greater than the Forward Floor Price but less than or equal to $85.61 (the &quot;Forward Cap Price&quot;), a delivery of shares equal to (i) the Forward Floor Price divided by the Settlement Price times (ii) 1/10 of the Maximum Number of shares of Common Stock, subject to rounding; and (c) if the Settlement Price were greater than the Forward Cap Price, a delivery of shares equal to (i) (A) the Forward Floor Price plus (B) the Settlement Price minus the Forward Cap Price, divided by (ii) the Settlement Price, times (iii) 1/10 of the Maximum Number of shares of Common Stock, subject to rounding.</footnote>
        <footnote id="F4">The Settlement Price on each of the Valuation Dates ranged from a high of $2.48 to a low of $1.87, resulting in CV Starr delivering to Credit Suisse the Maximum Number of shares of Common Stock.</footnote>
        <footnote id="F5">CV Starr may be deemed to be the beneficial owner of, and to have a pecuniary interest in, the shares of Common Stock held by the C.V. Starr &amp; Co., Inc. Trust, of which CV Starr is a beneficiary.</footnote>
    </footnotes>

    <remarks>C. V. Starr &amp; Co., Inc. (&quot;CV Starr&quot;) may be deemed to beneficially own more than 10% of the common stock of American International Group, Inc. under Rule 16a-1(a)(1) under the Securities Exchange Act of 1934, as amended (the &quot;Exchange Act&quot;), as a result of it being deemed a member of a group under Section 13(d)(3) of the Exchange Act.</remarks>

    <ownerSignature>
        <signatureName>/s/Bertil P-H Lundqvist, Attorney-In-Fact</signatureName>
        <signatureDate>2008-11-19</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/Mike F. Huang, Attorney-In-Fact</signatureName>
        <signatureDate>2008-11-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
