<SEC-DOCUMENT>0001179110-15-015843.txt : 20151204
<SEC-HEADER>0001179110-15-015843.hdr.sgml : 20151204
<ACCEPTANCE-DATETIME>20151204162631
ACCESSION NUMBER:		0001179110-15-015843
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20151130
FILED AS OF DATE:		20151204
DATE AS OF CHANGE:		20151204

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			OSI SYSTEMS INC
		CENTRAL INDEX KEY:			0001039065
		STANDARD INDUSTRIAL CLASSIFICATION:	SEMICONDUCTORS & RELATED DEVICES [3674]
		IRS NUMBER:				330238801
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		12525 CHADRON AVE
		CITY:			HAWTHORNE
		STATE:			CA
		ZIP:			90250
		BUSINESS PHONE:		3109780516

	MAIL ADDRESS:	
		STREET 1:		12525 CHADRON AVENUE
		CITY:			HAWTHORNE
		STATE:			CA
		ZIP:			90250

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Ong Chee Cheong Nicholas
		CENTRAL INDEX KEY:			0001628387

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-23125
		FILM NUMBER:		151270395

	MAIL ADDRESS:	
		STREET 1:		12525 CHADRON AVENUE
		CITY:			HAWTHORNE
		STATE:			CA
		ZIP:			90250
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>FORM 4/A -
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2015-11-30</periodOfReport>

    <dateOfOriginalSubmission>2015-12-02</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001039065</issuerCik>
        <issuerName>OSI SYSTEMS INC</issuerName>
        <issuerTradingSymbol>OSIS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001628387</rptOwnerCik>
            <rptOwnerName>Ong Chee Cheong Nicholas</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>12525 CHADRON AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HAWTHORNE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90250</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Pres., Spacelabs Healthcare</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-11-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>93.63</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>59993</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-12-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>94.67</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>56993</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $93.52 to $93.86. The reporting person undertakes to provide to OSI Systems, Inc., any security holder of OSI Systems, Inc., or staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.</footnote>
        <footnote id="F2">The reporting person's sale of 1,000 shares of OSI Systems, Inc. common stock on December 1, 2015 was matchable under Section 16(b) of the Securities Exchange Act of 1934 with a purchase of 1,000 shares on August 7, 2015 at a price of $67.00. The reporting person has delivered payment to OSI Systems, Inc., representing the full amount of the profit realized in connection with this short-swing transaction.</footnote>
        <footnote id="F3">The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $94.03 to $95.15. The reporting person undertakes to provide to OSI Systems, Inc., any security holder of OSI Systems, Inc., or staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Nicholas Ong</signatureName>
        <signatureDate>2015-12-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
