<SEC-DOCUMENT>0001225208-17-013561.txt : 20170809
<SEC-HEADER>0001225208-17-013561.hdr.sgml : 20170809
<ACCEPTANCE-DATETIME>20170809205607
ACCESSION NUMBER:		0001225208-17-013561
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170807
FILED AS OF DATE:		20170809
DATE AS OF CHANGE:		20170809

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CAVE GEORGE H
		CENTRAL INDEX KEY:			0001184583

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-30419
		FILM NUMBER:		171019475

	MAIL ADDRESS:	
		STREET 1:		C O ON SEMICONDUCTOR ATTN M ROGERS
		STREET 2:		5005 E MCDOWELL RD MDA700
		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>2017-08-07</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001184583</rptOwnerCik>
            <rptOwnerName>CAVE GEORGE H</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>EVP, Gen Cnsl, CC&amp;EO, &amp; Sec</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionDate>
                <value>2017-08-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>110988.0000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.0000</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>363549.0000</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionDate>
                <value>2017-08-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>26110.0000</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>16.3300</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>337439.0000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">This Form 4 reports the acquisition on August 7, 2017 of 110,988 Performance Based Restricted Stock Units (&quot;PBRSUs&quot;) from the attainment of a performance goal under an award made to the Reporting Person on March 7, 2016 (the &quot;2016 PBRSU Award&quot;).  The 2016 PBRSU Award covered a performance period of six consecutive fiscal quarters beginning with the quarter commencing January 1, 2016 (the &quot;Performance Measurement Period&quot;), and the number of shares eligible for vesting was based upon the Issuer achieving certain Adjusted Non-GAAP EBITDA, market share growth, and revenue growth performance goals.  As a result of the Issuer's achievement of the Adjusted Non-GAAP EBITDA performance goals for the Performance Measurement Period, the acquired PBRSUs will vest in two equal tranches, with the first tranche having vested on August 7, 2017.</footnote>
        <footnote id="F2">Includes an aggregate of 403 shares acquired by the Reporting Person under the Issuer's Employee Stock Purchase Plan for the fiscal quarter ended June 30, 2017.</footnote>
        <footnote id="F3">This disposition transaction reflects shares withheld by the Issuer in connection with the 2016 PBRSU Award.  On August 7, 2017, certain of the PBRSUs under the 2016 PBRSU Award vested.  Certain of the shares underlying such PBRSUs were withheld to satisfy the Reporting Person's 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>2017-08-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
