Exhibit 99.1

NEWS RELEASE

BBSI
ANNOUNCES THIRD QUARTER 2005 OPERATING RESULTS AND
FINANCIAL GUIDANCE FOR 4Q05

        PORTLAND, OREGON, October 26, 2005 — Barrett Business Services, Inc. (Nasdaq: BBSI) reported today net income of $4,340,000 for the third quarter ended September 30, 2005, an improvement of $1,892,000 or 77.3% over net income of $2,448,000 for the third quarter of 2004. Diluted earnings per share for the 2005 third quarter were $.40, as compared to diluted earnings per share of $.26 for the same quarter a year ago. Per share amounts for 2004 have been adjusted for a 3-for-2 stock split effected on May 19, 2005.

        Net revenues for the third quarter ended September 30, 2005 totaled $64.6 million, an increase of approximately $9.9 million or 18.1% over the $54.7 million for the same quarter in 2004.

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Barrett Business Services, Inc.
News Release – Third Quarter 2005
October 26, 2005

        The Company changed its reporting of PEO revenues from a gross basis to a net basis in 2002. The gross revenues and cost of revenues information below, although not in accordance with generally accepted accounting principles (“GAAP”), are presented for comparison purposes and because management believes such information is more informative as to the level of the Company’s business activity and more useful in managing its operations.

        Gross revenues of $212.1 million for the third quarter ended September 30, 2005 rose 46.2% over the similar period in 2004. For the nine months ended September 30, 2005, gross revenues of $552.7 million increased 41.6% over the comparable period in 2004.

        A reconciliation of non-GAAP gross revenues to net revenues is as follows:

For the third quarters ended September 30, 2005 and 2004 (in thousands):

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Barrett Business Services, Inc.
News Release – Third Quarter 2005
October 26, 2005

For the nine months ended September 30, 2005 and 2004 (in thousands):

        William W. Sherertz, President and Chief Executive Officer, commented that: “We are pleased with another solid quarter of operating results which were driven by continued strong growth in revenues.”

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Barrett Business Services, Inc.
News Release – Third Quarter 2005
October 26, 2005

        The following summarizes the unaudited consolidated balance sheets at September 30, 2005 and December 31, 2004.

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Barrett Business Services, Inc.
News Release – Third Quarter 2005
October 26, 2005

Outlook for Fourth Quarter 2005

        The Company also disclosed today limited financial guidance with respect to its operating results for the fourth quarter ending December 31, 2005. The Company expects gross revenues for the fourth quarter of 2005 to range from $204 million to $208 million, an increase of approximately 35% over the fourth quarter of 2004, and anticipates diluted earnings per share for the fourth quarter of 2005 to range from $.35 to $.37 per share, an increase of approximately 33% over $.27 per share for the same period a year ago, on a split-adjusted basis. Management’s outlook for fourth quarter of 2005 gross revenues as compared to the third quarter of 2005 reflects anticipated seasonality. A reconciliation of estimated gross revenues to estimated GAAP net revenues for the fourth quarter of 2005 is not included because the details of total gross revenues, such as PEO revenues and cost of PEO revenues, for the period are not reasonably estimable.

        On October 27, 2005 at 9:00 a.m. Pacific Time, William W. Sherertz and Michael D. Mulholland will host an investor telephone conference call to discuss third quarter 2005 operating results. To participate in the call, dial (877) 356-3717. The call identification number is 1259435. The conference call will also be webcast live at www.barrettbusiness.com. To access the webcast, click on the Investor Relations section of the Web site and select Webcast. A replay of the call will be available beginning October 27, 2005 at 11:00 a.m. and ending on November 3, 2005. To listen to the recording, dial (800) 642-1687 and enter conference identification code 1259435.

        BBSI provides a comprehensive range of human resource management solutions to large and small companies throughout many regions of the United States.

        Statements in this release about future events or performance, including earnings expectations for the fourth quarter of 2005, are forward-looking statements, which involve known and unknown risks, uncertainties and other factors that may cause the actual results of the Company to be materially different from any future results expressed or implied by such forward-looking statements. Factors that could affect future results include economic conditions in the Company’s service areas, the effect of changes in the Company’s mix of services on gross margin, future workers’ compensation claims experience, the effect of changes in the workers’ compensation regulatory environment in one or more of our primary markets, collectibility of accounts receivable, and the use of net proceeds of approximately $33.1 million and other effects of the Company’s recent follow-on equity offering, among others. Other important factors that may affect the Company’s future prospects are described in the Company’s 2004 Annual Report on Form 10-K. Although forward-looking statements help to provide complete information about the Company, readers should keep in mind that forward-looking statements may be less reliable than historical information. The Company undertakes no obligation to update or revise forward-looking statements in this release to reflect events or changes in circumstances that occur after the date of this release.

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