Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the incorporation by reference in the following Registration Statements:

(1) Registration Statements (Form S-8 Nos. 333-159007, 333-140602, 333-66344) pertaining to the Administaff, Inc. 2001 Incentive Plan

(2) Registration Statement (Form S-8 No. 333-151275) pertaining to the Administaff, Inc. 2008 Employee Stock Purchase Plan

(3) Registration Statement (Form S-8 No. 333-118790) pertaining to the Administaff, Inc. Directors Compensation Plan

(4) Registration Statements (Form S-8 Nos. 333-85151, 333-66342) pertaining to the Administaff, Inc. Non-Qualified Stock Option Plan, and

(5) Registration Statement (Form S-8 No. 333-85151, 333-34041) pertaining to the Administaff, Inc. 1997 Incentive Plan;

of our reports dated February 14, 2011, with respect to the consolidated financial statements of Administaff, Inc. and the effectiveness of internal control over financial reporting of Administaff, Inc. included in this Annual Report (Form 10-K) of Administaff, Inc for the year ended December 31, 2010.

/s/Ernst & Young LLP

Houston, Texas

February 14, 2011