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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-02-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001011109</issuerCik>
        <issuerName>ROBERTS REALTY INVESTORS INC</issuerName>
        <issuerTradingSymbol>RPI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000084353</rptOwnerCik>
            <rptOwnerName>ROBERTS CHARLES S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>450 NORTHRIDGE PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 302</rptOwnerStreet2>
            <rptOwnerCity>ATLANTA</rptOwnerCity>
            <rptOwnerState>GA</rptOwnerState>
            <rptOwnerZipCode>30350</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman, CEO, President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Units of Limited Partnership Interest</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-02-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2530</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.69</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2530</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>950092</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The acquired units are of Roberts Properties Residential, L.P. of which the issuer is the general partner.</footnote>
        <footnote id="F2">Units are redeemable at any time either for an equal number of shares of the issuer's common stock, or at the issuer's election, for cash equal to the fair market value of the underlying shares.  The issuer has adopted a policy of issuing shares in exchange for units.</footnote>
        <footnote id="F3">Of the total units beneficially owned by the reporting person, 29,500 units are owned by a family limited liability company, of which Mr. Roberts is the manager; the remaining units are owned directly.  Mr. Roberts disclaims beneficial ownership of those units held by the family limited liability company.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/e/Charles Elliott, Attorney-in-fact</signatureName>
        <signatureDate>2006-02-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
