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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-02-06</periodOfReport>

    <issuer>
        <issuerCik>0000814898</issuerCik>
        <issuerName>HILB ROGAL &amp; HOBBS CO</issuerName>
        <issuerTradingSymbol>HRH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001297893</rptOwnerCik>
            <rptOwnerName>Thompson Warren M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>HILB ROGAL &amp; HOBBS COMPANY</rptOwnerStreet1>
            <rptOwnerStreet2>4951 LAKE BROOK DRIVE, SUITE 500</rptOwnerStreet2>
            <rptOwnerCity>GLEN ALLEN</rptOwnerCity>
            <rptOwnerState>VA</rptOwnerState>
            <rptOwnerZipCode>23060</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-02-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>67</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>38.67</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3963</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Options (Right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>34.97</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-01-21</value>
            </exerciseDate>
            <expirationDate>
                <value>2011-07-21</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Options (Right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>36.49</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-11-04</value>
            </exerciseDate>
            <expirationDate>
                <value>2012-05-04</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F2">Nonemployee Directors Stock Incentive Plan grants shares of common stock of Company to Director in lieu of cash fees. Grants are increased by 30% if director elects to receive 100% of compensation in common stock to encourage maximization of at-risk compensation. Shares are physically issued quarterly and are rounded down to the nearest whole number.</footnote>
        <footnote id="F1">Directors' Deferred Plan purchases common stock of Company, which is held in trust under the terms of the Hilb, Rogal and Hamilton Amended and Restated Outside Directors Deferral Plan. Directors electing to receive 100% of compensation in common stock receive a 30% bonus grant of stock to encourage maximazation of at-risk compensation. Dividends are reinvested by the trustee. Deferred stock will be paid out in shares at the time selected by the director, either a lump sum or a series of distributions over a period of years.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Walter L. Smith</signatureName>
        <signatureDate>2006-02-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
