Registration No. 333-              

As filed with the Securities and Exchange Commission on April 27, 2011

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT UNDER

THE SECURITIES ACT OF 1933

OSI SYSTEMS, INC.

(Exact name of registrant as specified in its charter)

12525 Chadron Avenue

Hawthorne, California 90250

(Address of Principal Executive Offices) (Zip Code)

Amended and Restated 2006 Equity Participation Plan

(Full title of the plan)

Deepak Chopra

President and Chief Executive Officer

12525 Chadron Avenue

Hawthorne, California 90250

(310) 978-0516

(Name, address and telephone number of agent for service)

Indicated by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in rule 12b-2 of the Exchange Act (Check one):

CALCULATION OF REGISTRATION FEE

EXPLANATORY NOTE

At OSI Systems, Inc.’s (the “Registrant’s”) 2010 Annual Meeting of Stockholders on November 30, 2010 (the “Annual Meeting”), the stockholders approved an amendment to the Registrant’s Amended and Restated 2006 Equity Participation Plan (the “2006 Plan”) to increase the authorized shares under the 2006 Plan by 1,350,000.

This Registration Statement has been prepared and filed pursuant to and in accordance with the requirements of General Instruction E to Form S-8 for the purpose of effecting the registration under the Securities Act of the additional shares of common stock issuable under the 2006 Plan.  Pursuant to General Instruction E to Form S-8, the registrant hereby incorporates herein by reference the contents of the Registration Statement previously filed on Form S-8 (File No. 333-148936) on January 30, 2008 by the Registrant, as amended by Amendment No. 1 to the Registrant’s Registration Statement on Form S-8 filed on March 9, 2010.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

The following documents, which have been filed with the SEC by the Registrant are incorporated herein by reference and made a part hereof:

All documents filed by the Registrant pursuant to Section 13(a), 13(c), 14 and 15(d) of the Exchange Act, after the date of this Registration Statement and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold are incorporated by reference in this Registration Statement and are part hereof from the date of filing such documents. A report on Form 8-K furnished to the SEC shall not be incorporated by reference into this Registration Statement. Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the Registrant, OSI Systems, Inc., a corporation organized under the laws of the State of Delaware, certifies that it has reasonable grounds to believe that it meets all the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Hawthorne, California, as of April 27, 2011.

Each of the undersigned hereby constitutes and appoints Messrs. Alan Edrick, Chief Financial Officer, and Victor Sze, General Counsel, and each of them, as his attorneys-in-fact and agents, with full power of substitution and resubstitution for him or her in any and all capacities, to sign any and all amendments or post-effective amendments to this Registration Statement, and to file the same, with exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto each of such attorneys-in-fact and agents full power and authority to do and perform each and every act and thing requisite and necessary in connection with such matters and hereby ratifying and confirming all that each of such attorneys-in-fact and agents or his substitutes may do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed below by the following persons in the capacities and on the dates indicated.

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INDEX TO EXHIBITS

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EXHIBIT 5.1

OPINION OF LOEB & LOEB LLP

April 27, 2011

OSI Systems, Inc.

12525 Chadron Avenue

Hawthorne, California 90250

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

This opinion letter is furnished to you in connection with your filing of a registration statement on Form S-8, (the “Registration Statement”), pursuant to the Securities Act of 1933, as amended (the “Securities Act”), on or about the date hereof relating to the registration of up to 1,350,000 shares of Common Stock, $0.001 par value per share (the “Shares”), of OSI Systems Inc., a Delaware corporation (the “Company”), that may be issued pursuant to the Company’s Amended and Restated 2006 Equity Participation Plan (the “Plan”).

We have reviewed such documents and made such examination of law as we have deemed appropriate to give the opinions expressed below. We have relied, without independent verification, on certificates of public officials and, as to matters of fact material to the opinion set forth below, on certificates of officers of the Company.

The opinion expressed below is limited to the Delaware General Corporation Law (which includes applicable provisions of the Delaware Constitution and reported judicial decisions interpreting the Delaware General Corporation Law and the Delaware Constitution).

For purposes of the opinion expressed below, we have assumed that a sufficient number of authorized but unissued shares of the Company’s Common Stock will be available for issuance when the Shares are issued.

Based on the foregoing, we are of the opinion that the Shares have been duly authorized and, upon issuance and delivery against payment therefor in accordance with the terms of the Plan, will be validly issued, fully paid and nonassessable.

We hereby consent to the inclusion of this opinion as Exhibit 5.1 to the Registration Statement. In giving our consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations thereunder.

EXHIBIT 23.3

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement on Form S-8 of our reports dated August 27, 2010 relating to the financial statements and financial statement schedule of OSI Systems, Inc., and the effectiveness of internal controls over financial reporting, appearing in the Annual Report on Form 10-K of OSI Systems, Inc. for the year ended June 30, 2010.