Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN 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 *
BLAZER RANDOLPH C
  2. Issuer Name and Ticker or Trading Symbol
ON ASSIGNMENT INC [ASGN]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President, Apex Systems
(Last)
(First)
(Middle)
ON ASSIGNMENT, INC., 26745 MALIBU HILLS ROAD
3. Date of Earliest Transaction (Month/Day/Year)
12/31/2017
(Street)

CALABASAS, CA 91301
4. If Amendment, Date Original Filed(Month/Day/Year)
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 Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 12/31/2017   A   5,379 (1) A $ 0 52,154 D  
Common Stock 12/31/2017   F   2,659 (2) D $ 64.27 49,495 D  
Common Stock 12/31/2017   A   2,241 (1) A $ 0 51,736 D  
Common Stock 12/31/2017   F   1,108 (2) D $ 64.27 50,628 D  
Common Stock 12/31/2017   A   1,794 (1) A $ 0 52,422 D  
Common Stock 12/31/2017   F   887 (2) D $ 64.27 51,535 D  
Common Stock 12/31/2017   A   3,428 (1) A $ 0 54,963 D  
Common Stock 12/31/2017   F   1,695 (2) D $ 64.27 53,268 D  
Common Stock 12/31/2017   A   3,586 (1) A $ 0 56,854 D  
Common Stock 12/31/2017   F   1,773 (2) D $ 64.27 55,081 D  
Common Stock 12/31/2017   A   10,756 (3) A $ 0 65,837 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
BLAZER RANDOLPH C
ON ASSIGNMENT, INC.
26745 MALIBU HILLS ROAD
CALABASAS, CA 91301
      President, Apex Systems  

Signatures

 By: /s/ Jennifer Painter, CLO For: Randolph C. Blazer   01/03/2018
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(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) The acquired shares vested upon certification of a performance target on December 31, 2017 for a performance award previously granted to the executive officer.
(2) Executive Officer elected to satisfy his tax withholding obligations upon vesting by having the issuer withhold a number of vested shares equal to that of the officer's tax liability.
(3) On December 31, 2017, performance targets were achieved for an RSU grant that was previously made to the executive officer. 50% of these RSUs will vest on January 3, 2019 and the remaining RSUs will vest on January 3, 2020, subject to the executive officer's continued service to the Company.

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