EXHIBIT 24

POWER OF ATTORNEY

Each person whose signature appears below designates and appoints WILLIAM
W. SHERERTZ and MICHAEL D. MULHOLLAND, and either of them, true and lawful
attorneys-in-fact and agents, to sign the Annual Report on Form 10-K for the
year ended December 31, 2004, of Barrett Business Services, Inc., a Maryland
corporation, and to file said report, with all exhibits thereto, with the
Securities and Exchange Commission under the Securities Exchange Act of 1934.
Each person whose signature appears below also grants to these attorneys-in-fact
and agents full power and authority to perform every act and execute any
instruments that they deem necessary or desirable in connection with said
report, as fully as he or she could do in person, hereby ratifying and
confirming all that the attorneys-in-fact and agents or their substitutes may
lawfully do or cause to be done.

IN WITNESS WHEREOF, this power of attorney has been executed by each of
the undersigned as of this 21st day of March, 2005.

Signature Title
--------- -----


/s/ William W. Sherertz President and Chief Executive Officer and
- ------------------------- Director
William W. Sherertz (Principal Executive Officer)


/s/ Michael D. Mulholland Vice President-Finance and Secretary
- ------------------------- (Principal Financial Officer)
Michael D. Mulholland


/s/ James D. Miller Controller
- ------------------------- (Principal Accounting Officer)
James D. Miller


/s/ Thomas J. Carley Director
- -------------------------
Thomas J. Carley


/s/ James B. Hicks Director
- -------------------------
James B. Hicks


/s/ Jon L. Justesen Director
- -------------------------
Jon L. Justesen


/s/ Anthony Meeker Director
- -------------------------
Anthony Meeker


/s/ Nancy B. Sherertz Director
- -------------------------
Nancy B. Sherertz