VANCOUVER, BRITISH COLUMBIA -- (Marketwire) -- 09/23/08 -- Rimfire Minerals Corporation (TSX VENTURE: RFM) is pleased to announce that in partnership with Northgate Minerals Corporation (TSX: NGX) drilling has commenced at its new gold discovery on the Boulevard Property. The Boulevard Property is located approximately 135 kilometres south of Dawson City, Yukon. Gold bearing mineralization, including 7.04 g/t gold over 6.0 metres, was discovered in two of three trenches over a 300 metre trend (see Rimfire news release PR08-12, August 20, 2008). The diamond drilling program will consist of 4 to 6 holes averaging 150 metres in length and is expected to be completed by mid-October.

The current program was initiated after this summer's discovery of gold-bearing mineralization in trenches testing anomalous arsenic-antimony-gold soil geochemistry at the Boulevard. Chip sampling from the first trench (TRBV08-01) yielded 7.04 g/t gold over 6.0 metres. One hundred metres southeast, trench TRBV08-02 returned 6.43 g/t gold over 2.0 metres. Gold mineralization is hosted in strongly sericite-clay altered schists with disseminated pyrite, arsenopyrite, stibnite and specular hematite that envelopes quartz and massive stibnite veins. Additional soil sampling undertaken in conjunction with trenching has now expanded the target to an area of 2.0 by 0.4 kilometres. Drilling will aim to test mineralization encountered in the trenches at depth. Soil sampling and a reconnaissance IP geophysical survey has commenced to help expand the target, as well as refine drill hole locations along trend.

This program is being conducted under an exploration alliance agreement with Northgate Minerals signed in December, 2005. The Boulevard Property is held jointly by Rimfire and Northgate, with each company having funded the initial $330,000 in targeting and exploration that led to staking of the property. To date, Northgate has funded approximately $435,000 of the required $1.5 million in exploration expenditures to earn an additional 10% interest (for a total of 60%) in the property.

This news release has been reviewed by Mark Baknes, M.Sc., P.Geo., VP Exploration of Rimfire Minerals, a Qualified Person for the purpose of National Instrument 43-101.

About Rimfire

Rimfire Minerals Corporation is an aggressive, well-financed mineral exploration company with a portfolio of highly prospective gold and copper properties in western North America and Australia. Rimfire currently has in excess of two years of operating capital, and finances approximately 80% of its exploration through option and joint venture agreements. Current and former partners include AngloGold Ashanti Limited, Barrick Gold Corporation, Newmont Mining Company, Inmet Mining Corporation, Northgate Minerals Corporation, Fronteer Development Group Inc., Rubicon Minerals Corporation, American Creek Resources Ltd., Island Arc Exploration Corporation, Jaguar Minerals Limited and BWG.

About Northgate Minerals

Northgate Minerals Corporation is a mid-tier gold and copper producer with mining operations, development projects and exploration properties in Canada and Australia. The company is forecasting over 385,000 ounces of unhedged gold production in 2008 and is targeting growth through further acquisition opportunities in stable mining jurisdictions around the world.

On behalf of Rimfire Minerals Corporation

Jason Weber, P.Geo., President & CEO

CAUTIONARY STATEMENT: No stock exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein. This News Release includes certain "forward-looking statements". Other than statements of historical fact, all statements included in this release, including, without limitation, statements regarding future plans and objectives of Rimfire Minerals Corporation, are forward-looking statements that involve various risks and uncertainties. There can be no assurance that such statements will prove to be accurate, and actual results and future events could differ materially from those anticipated in such statements. Important factors that could cause actual results to differ materially from Rimfire's expectations are the risks detailed herein and from time to time in the filings made by Rimfire Minerals Corporation with securities regulators. Those filings can be found on the Internet at http://www.sedar.com and http://www.sec.gov/edgar/searchedgar...

Contacts:
Rimfire Minerals Corporation
Patrick Moodie
(604) 669-6660

Rimfire Minerals Corporation
Jason Weber
(604) 669-6660
(604) 669-0898 (FAX)
Email: [email protected]
Website: www.rimfireminerals.com