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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-11-19</periodOfReport>

    <issuer>
        <issuerCik>0001090872</issuerCik>
        <issuerName>AGILENT TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>A</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001235113</rptOwnerCik>
            <rptOwnerName>KOH BOON HWEE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5301 STEVENS CREEK BLVD, MS 1A-LC</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SANTA CLARA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95051</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Employee Director Stock Option (right to buy)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>35.8</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-11-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>6302</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2017-11-18</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6302</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6302</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Right to buy Agilent Technologies, Inc. common stock granted under the Agilent Technologies, Inc. 1999 Non-Employee Director Stock Plan.</footnote>
        <footnote id="F2">The option becomes exercisable in four increments, of 25% each, and vests initially upon the annual stockholders meeting following the grant date.  The second, third and fourth vesting date shall be the dates six months, nine months and one year, respectively, following the grant date.  The option is forfeited if a non-employee director terminates service at or before the annual stockholders meeting following the grant date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Marie Oh Huber, Attorney-in-fact for Mr. Koh</signatureName>
        <signatureDate>2007-11-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
