Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  McKenna Thomas Joseph
 2. Date of Event Requiring Statement (Month/Day/Year)
12/11/2008		 3. Issuer Name and Ticker or Trading Symbol
ON ASSIGNMENT INC [ASGN]
(Last)
(First)
(Middle)
ON ASSIGNMENT, INC., 26651 WEST AGOURA ROAD		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Senior Vice President
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

CALABASAS, CA 91302		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock 22,575
D
 

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Incentive Stock Option (right to buy)   (1) 12/10/2014 Common Stock 292 $ 4.96 D  
Incentive Stock Option (right to buy)   (1) 02/17/2014 Common Stock 2,917 $ 7 D  
Non-Qualified Stock Option (right to buy)   (2) 09/04/2018 Common Stock 10,000 $ 9.14 D  
Non-Qualified Stock Option (right to buy)   (3) 09/06/2017 Common Stock 2,000 $ 10.38 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
McKenna Thomas Joseph
ON ASSIGNMENT, INC.
26651 WEST AGOURA ROAD
CALABASAS, CA 91302		       Senior Vice President  

Signatures

By: Power of Attorney, James L. Brill For: Thomas J. McKenna 12/19/2008
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) All of these options are currently exercisable.
(2) These options vest one-fourth of the total number of shares after twelve months from the grant date, and one forty-eighth of such amount with respect to each month thereafter.
(3) 625 of these options are currently exercisable and the remaining 1,375 shares will vest at a rate of approximately 42 options per month.

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