<SUBMISSION>
<ACCESSION-NUMBER>0001266066-08-000013
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20080802
<FILING-DATE>20080804
<DATE-OF-FILING-DATE-CHANGE>20080804
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>CIENA CORP
<CIK>0000936395
<ASSIGNED-SIC>3661
<IRS-NUMBER>232725311
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1031
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>1201 WINTERSON ROAD
<CITY>LINTHICUM
<STATE>MD
<ZIP>21090
<PHONE>4108658500
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>1201 WINTERSON ROAD
<CITY>LINTHICUM
<STATE>MD
<ZIP>21090
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>SMITH ARTHUR D
<CIK>0001266066
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-21969
<FILM-NUMBER>08988275
</FILING-VALUES>
<BUSINESS-ADDRESS>
<PHONE>410-694-5700
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>1201 WINTERSON ROAD
<CITY>LINTHICUM
<STATE>MD
<ZIP>21090
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-08-02</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000936395</issuerCik>
        <issuerName>CIENA CORP</issuerName>
        <issuerTradingSymbol>CIEN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001266066</rptOwnerCik>
            <rptOwnerName>SMITH ARTHUR D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CIENA CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>1201 WINTERSON ROAD</rptOwnerStreet2>
            <rptOwnerCity>LINTHICUM,</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21090</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CHIEF OPERATING OFFICER</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-08-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>455</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.89</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>93821</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares reported represent the amount forfeited to cover the tax liabilities of the reporting person pursuant to a restricted stock unit (RSU) award agreement dated November 1, 2005.  The RSU vests at the end of Ciena's fiscal quarters over a four year year term and shares are issued net of taxes upon vesting.  Acquisition of the RSU was previously reported in Table I of reporting person's Form 4 filed on November 3, 2005.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Erik Lichter  For: Arthur D. Smith</signatureName>
        <signatureDate>2008-08-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
