<SUBMISSION>
<ACCESSION-NUMBER>0001032553-08-000009
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20080509
<FILING-DATE>20080513
<DATE-OF-FILING-DATE-CHANGE>20080513
<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 GARY B
<CIK>0001032553
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>000-21969
<FILM-NUMBER>08827806
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>1201 WINTERSON ROAD
<CITY>LINTHICUM
<STATE>MD
<ZIP>21090
<PHONE>4108658500
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>C/O CIENA CORPORATION
<STREET2>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>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-05-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001032553</rptOwnerCik>
            <rptOwnerName>SMITH GARY B</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>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>PRESIDENT, CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-05-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3840</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>16.52</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>172053</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-05-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3840</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.5626</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>168213</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Qualified Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>16.52</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-05-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3840</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-11-02</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3840</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>64717</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Sales were effected pursuant to Rule 10b5-1 trading plan dated June 22, 2007.</footnote>
        <footnote id="F2">Reflects the average sale price of the total shares sold.  Actual sale prices are as follows:  100 shares at $32.63; 100 shares at $32.67; 100 shares at $32.80; 100 shares at $32.93; 100 shares at $32.60; 100 shares at $32.46; 100 shares at $32.47; 100 shares at $32.85; 100 shares at $32.77; 100 shares at $32.73; 100 shares at $32.74; 100 shares at $32.84; 100 shares at $32.97; 100 shares at $32.88; 100 shares at $32.70; 200 shares at $32.58; 100 shares at $32.57; 100 shares at $32.64; 100 shares at $32.62; 100 shares at $32.55; 200 shares at $32.37; 100 shares at $32.39; 100 shares at $32.29; 200 shares at $32.25; 100 shares at $32.26; 200 shares at $32.41; 100 shares at $32.53; 100 shares at $32.60; 100 shares at $32.48; 100 shares at $32.44; 100 shares at $32.50; 100 shares at $32.51; 140 shares at $32.28; and 100 shares at $32.57.</footnote>
        <footnote id="F3">Option vests in equal monthly amounts over 48 months beginning on November 1, 2005.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Erik Lichter  For: Gary B. Smith</signatureName>
        <signatureDate>2008-05-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
