Exhibit 23

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement on Form S-8 (No. 333-48313) of PS Business Parks, Inc. pertaining to the PS Business Parks, Inc. 1997 Stock Option and Incentive Plan, the Registration Statement on Form S-8 (No. 333-50274) of PS Business Parks, Inc. pertaining to the PS 401(k)/Profit Sharing Plan, the Registration Statement on Form S-8 (No. 333-104604) of PS Business Parks, Inc. pertaining to the PS Business Parks, Inc. 2003 Stock Option and Incentive Plan, the Registration Statement on Form S-8 (No. 333-129463) of PS Business Parks, Inc. pertaining to the PS Business Parks, Inc. Retirement Plan for Non-Employee Directors and the Registration Statement on Form S-3 (No. 333-160104) and the related prospectus of our reports dated February 25, 2011 with respect to the consolidated financial statements and related financial statement schedule of PS Business Parks, Inc., and the effectiveness of internal control over financial reporting of PS Business Parks, Inc., included in this Annual Report on Form 10-K for the year ended December 31, 2010, filed with the Securities and Exchange Commission.

/s/  Ernst & Young LLP

Los Angeles, California

February 25, 2011