-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 QTgM9r3yZH68jg+MP3Q/n2n6xmwmkZuF+Vb0N+N84lY7Iir8phr+IluJ6t3p5xif
 FCS5Ve/V7URnlgkCv1m72Q==

<SEC-DOCUMENT>0000885725-03-000075.txt : 20030609
<SEC-HEADER>0000885725-03-000075.hdr.sgml : 20030609
<ACCEPTANCE-DATETIME>20030609144239
ACCESSION NUMBER:		0000885725-03-000075
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030605
FILED AS OF DATE:		20030609

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BOSTON SCIENTIFIC CORP
		CENTRAL INDEX KEY:			0000885725
		STANDARD INDUSTRIAL CLASSIFICATION:	SURGICAL & MEDICAL INSTRUMENTS & APPARATUS [3841]
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-19806
		FILM NUMBER:		03737293

	BUSINESS ADDRESS:	
		STREET 1:		ONE BOSTON SCIENTIFIC PL
		CITY:			NATICK
		STATE:			MA
		ZIP:			01760-1537
		BUSINESS PHONE:		5086508000

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CYBERONICS INC
		CENTRAL INDEX KEY:			0000864683
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTROMEDICAL & ELECTROTHERAPEUTIC APPARATUS [3845]
		IRS NUMBER:				760236465
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		16511 SPACE CENTER BLVD
		STREET 2:		SUITE 600
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77058
		BUSINESS PHONE:		7133321375

	MAIL ADDRESS:	
		STREET 1:		16511 SPACE CENTER BLVD
		STREET 2:		SUITE 600
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77058
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <documentType>4</documentType>

    <periodOfReport>2003-06-05</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000864683</issuerCik>
        <issuerName>CYBERONICS INC</issuerName>
        <issuerTradingSymbol>CYBX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000885725</rptOwnerCik>
            <rptOwnerName>BOSTON SCIENTIFIC CORP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>
        <transactionDate>
            <value>2003-06-05</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>P</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>400000</value>
            </transactionShares>
            <transactionValue>
                <value>20.27</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>3174000</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>

    <nonDerivativeSecurity>
        <securityTitle>
            <value>Common Stock</value>
        </securityTitle>
        <transactionDate>
            <value>2003-06-06</value>
        </transactionDate>
        <transactionCoding>
            <transactionFormType>4</transactionFormType>
            <transactionCode>P</transactionCode>
            <equitySwapInvolved>0</equitySwapInvolved>
        </transactionCoding>
        <transactionTimeliness>
            <value></value>
        </transactionTimeliness>
        <transactionAmounts>
            <transactionShares>
                <value>126000</value>
            </transactionShares>
            <transactionValue>
                <value>20.66</value>
            </transactionValue>
            <transactionAcquiredDisposedCode>
                <value>A</value>
            </transactionAcquiredDisposedCode>
        </transactionAmounts>
        <postTransactionAmounts>
            <sharesOwnedFollowingTransaction>
                <value>3300000</value>
            </sharesOwnedFollowingTransaction>
        </postTransactionAmounts>
        <ownershipNature>
            <directOrIndirectOwnership>
                <value>D</value>
            </directOrIndirectOwnership>
        </ownershipNature>
    </nonDerivativeSecurity>


    <ownerSignature>
        <signatureName>Lawrence J. Knopf, Vice President</signatureName>
        <signatureDate>2003-06-09</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----