<SEC-DOCUMENT>0001225208-17-018260.txt : 20171205
<SEC-HEADER>0001225208-17-018260.hdr.sgml : 20171205
<ACCEPTANCE-DATETIME>20171205170604
ACCESSION NUMBER:		0001225208-17-018260
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20171201
FILED AS OF DATE:		20171205
DATE AS OF CHANGE:		20171205

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			COLPITTS BERNARD RAYMOND JR
		CENTRAL INDEX KEY:			0001699662

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30419
		FILM NUMBER:		171240401

	MAIL ADDRESS:	
		STREET 1:		ON SEMICONDUCTOR C/O M. ROGERS M/D A700
		STREET 2:		5005 EAST MCDOWELL ROAD
		CITY:			PHOENIX
		STATE:			AZ
		ZIP:			85008-4229

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>2017-12-01</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001699662</rptOwnerCik>
            <rptOwnerName>COLPITTS BERNARD RAYMOND JR</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>Chief Accounting Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionDate>
                <value>2017-12-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>433.0000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>19.8600</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>22545.0000</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The disposition transaction represents shares withheld by the Issuer in connection with the vesting of certain restricted stock units under the restricted stock units award agreement entered into as of December 1, 2014 between the Issuer and the Reporting Person pursuant to the Issuer's Amended and Restated Stock Incentive Plan.  The reported shares were withheld to satisfy the Reporting Person's tax withholding obligations.  The Issuer will pay these taxes on behalf of the Reporting Person.</footnote>
        <footnote id="F2">Includes an aggregate of 445 shares acquired by the Reporting Person under the Issuer's Employee Stock Purchase Plan for the fiscal quarter ended September 29, 2017.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Mark N. Rogers, Attorney-in-Fact</signatureName>
        <signatureDate>2017-12-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
