<SEC-DOCUMENT>0001225208-19-002459.txt : 20190213
<SEC-HEADER>0001225208-19-002459.hdr.sgml : 20190213
<ACCEPTANCE-DATETIME>20190213165940
ACCESSION NUMBER:		0001225208-19-002459
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20190211
FILED AS OF DATE:		20190213
DATE AS OF CHANGE:		20190213

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HERNANDEZ EMMANUEL T
		CENTRAL INDEX KEY:			0001186773

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30419
		FILM NUMBER:		19598374

	MAIL ADDRESS:	
		STREET 1:		C/O MEMC ELECTRONIC MATERIALS, INC.
		STREET 2:		P O BOX 8
		CITY:			ST. PETERS
		STATE:			MO
		ZIP:			63376

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>2019-02-11</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001186773</rptOwnerCik>
            <rptOwnerName>HERNANDEZ EMMANUEL T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5005 EAST MCDOWELL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PHOENIX</rptOwnerCity>
            <rptOwnerState>AZ</rptOwnerState>
            <rptOwnerZipCode>85008</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionDate>
                <value>2019-02-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10000.0000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>22.0541</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>139655.0000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">This transaction was made pursuant to the Reporting Person's existing Rule 10b5-1 plan (i.e., a stock trading plan designed to comply with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended).</footnote>
        <footnote id="F2">This disposition transaction was executed in multiple trades at prices ranging from $22.00 to $22.17.  The price reported above reflects the weighted average sale price.  The Reporting Person hereby undertakes to provide, upon request, to the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Mark N. Rogers, Attorney-in-Fact</signatureName>
        <signatureDate>2019-02-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
