<SEC-DOCUMENT>0001225208-18-005699.txt : 20180307
<SEC-HEADER>0001225208-18-005699.hdr.sgml : 20180307
<ACCEPTANCE-DATETIME>20180307172733
ACCESSION NUMBER:		0001225208-18-005699
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180305
FILED AS OF DATE:		20180307
DATE AS OF CHANGE:		20180307

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Rolls Paul E
		CENTRAL INDEX KEY:			0001482082

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30419
		FILM NUMBER:		18674251

	MAIL ADDRESS:	
		STREET 1:		C/O ON SEMICONDUCTOR
		STREET 2:		5005 E MCDOWELL RD MD A700
		CITY:			PHOENIX
		STATE:			AZ
		ZIP:			85008

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ON SEMICONDUCTOR CORP
		CENTRAL INDEX KEY:			0001097864
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				363840979
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		5005 EAST MCDOWELL ROAD
		CITY:			PHOENIX
		STATE:			AZ
		ZIP:			85008
		BUSINESS PHONE:		6022446600

	MAIL ADDRESS:	
		STREET 1:		5005 EAST MCDOWELL ROAD
		CITY:			PHOENIX
		STATE:			AZ
		ZIP:			85008

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SCG HOLDING CORP
		DATE OF NAME CHANGE:	19991027
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-03-05</periodOfReport>

    <issuer>
        <issuerCik>0001097864</issuerCik>
        <issuerName>ON SEMICONDUCTOR CORP</issuerName>
        <issuerTradingSymbol>ON</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001482082</rptOwnerCik>
            <rptOwnerName>Rolls Paul E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5005 EAST MCDOWELL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PHOENIX</rptOwnerCity>
            <rptOwnerState>AZ</rptOwnerState>
            <rptOwnerZipCode>85008</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>Exec VP Sales &amp; Marketing</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionDate>
                <value>2018-03-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>28619.0000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.4600</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>326037.0000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionDate>
                <value>2018-03-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4190.0000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.4700</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>321847.0000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Restricted stock units approved on February 14, 2018 under the Issuer's Amended and Restated Stock Incentive Plan with a grant date of March 5, 2018 and with equal pro rata vesting over a 3-year period beginning on the first anniversary of the grant date.  The award may only be settled in shares of the Issuer's common stock upon vesting and was for no consideration other than service as an executive officer of the Issuer.</footnote>
        <footnote id="F2">This disposition transaction represents shares withheld by the Issuer in connection with the Reporting Person's 2017 restricted stock units award granted pursuant to the Issuer's Amended and Restated Stock Incentive Plan and related award agreement.  On March 6, 2018, certain of these units vested.  These shares are withheld to satisfy the Reporting Person's tax withholding obligations.  The Issuer will pay these taxes on behalf of the Reporting Person.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Mark N. Rogers, Attorney-in-Fact</signatureName>
        <signatureDate>2018-03-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
