Washington, D.C.  20549 

Under the Securities Exchange Act of 1934
Original Filing*

OSI Systems, Inc. 
(Name of Issuer)

Common Stock
(Title of Class of Securities)

(CUSIP Number)

December 31, 2004 
(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule 
is Filed:
     [ x ] Rule 13d-1(b)
     [   ] Rule 13d-1(c)
     [   ] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities,
and for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be
deemed to be filed for the purpose of Section 18 of the Securities
Exchange Act of 1934 (Act) or otherwise subject to the liabilities of that
section of the Act but shall be subject to all other provisions of the Act
(however, see the Notes). 


1. Names of Reporting Persons.
I.R.S. Identification Nos. of above persons (entities only)  
Strong Capital Management, Inc. 39-1213042 

2. Check the Appropriate Box if a Member of a Group (See Instructions) 

3. SEC Use Only

4. Citizenship or Place of Organization 
United States

Number of Shares Beneficially Owned by Each Reporting Person With:

5. Sole Voting Power

6. Shared Voting Power

7. Sole Dispositive Power

8. Shared Dispositive Power

9. Aggregate Amount Beneficially Owned by Each Reporting Person  

10. Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See
Instructions) N/A

11. Percent of Class Represented by Amount in Row (9) 

12. Type of Reporting Person (See Instructions) 

Item 1.
(a) Name of Issuer
OSI Systems, Inc. 

(b) Address of Issuer's Principal Executive Offices
12525 Chadron Avenue
Hawthorne, CA 90250 

Item 2.
(a) Name of Person Filing
Strong Capital Management, Inc. 

(b) Address of Principal Business Office  
Strong Capital Management, Inc.  
100 Heritage Reserve  
Menomonee Falls, WI 53051 

(c) Citizenship 
United States

(d) Title of Class of Securities 
Common Stock

(e) CUSIP Number

Item 3. If this statement is filed pursuant to ss.ss.240.13d-1(b) or
240.13d-2(b) or (c), check whether the person filing is a: 

(a) [ ] Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

(b) [ ] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

(c) [ ] Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C.

(d) [ ] Investment company registered under section 8 of the Investment Company
Act of 1940 (15 U.S.C. 80a-8).

(e) [x] An investment adviser in accordance with ss.240.13d-1(b)(1)(ii)(E).

(f) [ ] An employee benefit plan or endowment fund in accordance with

(g) [ ] A parent holding company or control person in accordance with

(h) [ ] A savings associations as defined in section 3(b) of the Federal Deposit
Insurance Act (12 U.S.C. 1813).

(i) [ ] A church plan that is excluded from the definition of an investment
company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C.

(j) [ ] Group, in accordance with ss.240.13d-1(b)(1)(ii)(J). 

Item 4. Ownership.

Provide the following information regarding the aggregate number and percentage
of the class of securities of the issuer identified in Item 1.

(a) Amount beneficially owned:  

(b) Percent of class: 

(c) Number of shares as to which the person has: 

(i) Sole power to vote or to direct the vote  

(ii) Shared power to vote or to direct the vote 

(iii) Sole power to dispose or to direct the disposition of  

(iv) Shared power to dispose or to direct the disposition of 

Item 5.  Ownership of Five Percent or Less of a Class
If this statement is being filed to report the fact that as of the date hereof
the reporting person has ceased to be the beneficial owner of more than five
percent of the class of securities, check the following [ ]. 

Item 6. Ownership of More than Five Percent on Behalf of Another Person. Strong
Capital Management, Inc. is a registered investment advisor whose clients have
the right to receive or the power to direct the receipt of dividends and the
proceeds from the sale of the securities reported on this Schedule. No
individual client's holdings represent more than five percent of the class of

Item 7.  Identification and Classification of the Subsidiary Which Acquired the 
Security Being Reported on By the Parent Holding Company
Not Applicable

Item 8.  Identification and Classification of Members of the Group
Not Applicable

Item 9.  Notice of Dissolution of Group
Not Applicable

Item 10.  Certification
By signing below I certify that, to the best of my knowledge and belief, the
securities referred to above were acquired and are held in the ordinary course
of business and were not acquired and are not held for the purpose of or with
the effect of changing or influencing the control of the issuer of the
securities and were not acquired and are not held in connection with or as a
participant in any transaction having that purpose or effect.


After reasonable inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and

Date:  February 11, 2005 

Strong Capital Management, Inc. 

By: /s/ John W. Widmer
John W. Widmer, Treasurer