CONSENT
OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We
consent to the incorporation by reference in Registration Statement Nos.
333-57078, 333-38849, 333-61998, 333-106203, 333-143907 and 333-148000 on Form
S-8 and 333-88034, 333-134479 and 333-142382 on Form S-3 of our reports dated
March 16, 2010 relating to the financial statements and financial statement
schedule of On Assignment, Inc. (the "Company") and the effectiveness of
the Company's internal control over financial reporting, appearing in this
Annual Report on Form 10-K of On Assignment, Inc. for the year ended December
31, 2009.
/s/ Deloitte & Touche
LLP
Los
Angeles, California
March 16,
2010