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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-02-16</periodOfReport>

    <issuer>
        <issuerCik>0000025232</issuerCik>
        <issuerName>COUSINS PROPERTIES INC</issuerName>
        <issuerTradingSymbol>CUZ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001056731</rptOwnerCik>
            <rptOwnerName>GELLERSTEDT LAWRENCE L III</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>191 PEACHTREE STREET</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 3600</rptOwnerStreet2>
            <rptOwnerCity>ATLANTA</rptOwnerCity>
            <rptOwnerState>GA</rptOwnerState>
            <rptOwnerZipCode>30303</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>President, COO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-02-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>14918</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-02-16</value>
            </exerciseDate>
            <expirationDate>
                <value>2013-02-16</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>14918</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14918</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>8.35</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-02-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>50138</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.35</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-02-16</value>
            </exerciseDate>
            <expirationDate>
                <value>2019-02-16</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>50138</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>50138</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Award of restricted stock units under Cousins Properties Incorporated (CPI) 2005 Restricted Stock Unit Plan. Each unit represents a right to receive a payment in cash equal to the average of the closing price of CPI's common stock on each trading day during the 30 day period ending on the date payment is due under the plan. These units will vest 25% per year on each anniversary date of the grant, with units being 100% vested in year 4 of the grant term. While the shares are being held prior to vesting, the reporting person will have the right to receive all cash dividends but will not have shareholder rights. All unvested shares will forfeit upon termination of employment.</footnote>
        <footnote id="F2">These options were granted under the 1999 Incentive Stock Plan.  These options will vest 25% per year on the anniversary of the grant date, with shares being 100% vested in year 4 of the grant term.  The reporting person may, as an alternative to exercising the stock option right to purchase CPI stock, elect to exercise the related Stock Appreciation Right (SAR).  The exercise of the SAR allows the reporting person to receive the number of whole shares of CPI stock equal to the difference between the fair market value of the stock on the date of exercise and the option price.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Lawrence L. Gellerstedt III</signatureName>
        <signatureDate>2009-02-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
