<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-11-13</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000898174</issuerCik>
        <issuerName>REINSURANCE GROUP OF AMERICA INC</issuerName>
        <issuerTradingSymbol>RGA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000728618</rptOwnerCik>
            <rptOwnerName>METROPOLITAN LIFE INSURANCE CO/NY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE MADISON AVENUE LAW DEPARTMENT</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10010-3690</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, Par Value $.01 Per Share</value>
            </securityTitle>
            <transactionDate>
                <value>2003-11-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2205000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.65</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2532600</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, Par Value $.01 Per Share</value>
            </securityTitle>
            <transactionDate>
                <value>2003-11-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>795000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.65</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24926250</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>

        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, Par Value $.01 Per Share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4784689</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote.</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>

    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These shares are directly owned by Equity Intermediary Company, which is a wholly-owned subsidiary of General American Life Insurance Company, which is a wholly-owned subsidiary of GenAmerica Financial Corporation, which is a wholly-owned subsidiary of Metropolitan Life Insurance Company.</footnote>
        <footnote id="F2">These shares are directly owned by Metropolitan Life Insurance Company, which is a wholly-owned subsidiary of MetLife, Inc., and previously reported on a Form 5 filed for December 2000.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>Anthony J. Williamson, Senior Vice-President and Treasurer</signatureName>
        <signatureDate>2003-11-17</signatureDate>
    </ownerSignature>

</ownershipDocument>
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X0201
4
2003-11-13
0
0000898174
REINSURANCE GROUP OF AMERICA INC
RGA
0000728618
METROPOLITAN LIFE INSURANCE CO/NY
ONE MADISON AVENUE LAW DEPARTMENT
NEW YORK
NY
10010-3690
0
0
1
0
Common Stock, Par Value $.01 Per Share
2003-11-13
4
P
0
2205000
36.65
A
2532600
D
Common Stock, Par Value $.01 Per Share
2003-11-13
4
P
0
795000
36.65
A
24926250
I
See Footnote.
Common Stock, Par Value $.01 Per Share
4784689
I
See Footnote.
These shares are directly owned by Equity Intermediary Company, which is a wholly-owned subsidiary of General American Life Insurance Company, which is a wholly-owned subsidiary of GenAmerica Financial Corporation, which is a wholly-owned subsidiary of Metropolitan Life Insurance Company.
These shares are directly owned by Metropolitan Life Insurance Company, which is a wholly-owned subsidiary of MetLife, Inc., and previously reported on a Form 5 filed for December 2000.
Anthony J. Williamson, Senior Vice-President and Treasurer
2003-11-17