Vancouver, British Columbia, Canada, 27 January 2009 – Ainsworth Lumber Co. Ltd. (TSX: ANS and ANS.WT) announced today that, based on a review by management of operational and market factors, the company has decided to permanently close its two northern Minnesota-based oriented strand board (OSB) mills in Cook and Bemidji, effective immediately.

The Cook mill has not been in production since January 2008, when operations were indefinitely curtailed. The Bemidji mill curtailed operations in October 2008. Before the closures, the Bemidji mill had an annual production capacity of approximately 350 million square feet (3/8-inch basis) and the Cook mill had an annual production capacity of approximately 450 million square feet (3/8-inch basis). Both mills were acquired by Ainsworth in 2004 as part of the acquisition of the OSB business of Potlatch Corporation.

Ainsworth’s third Minnesota mill at Grand Rapids, which also was acquired from Potlatch in 2004, was permanently closed in August 2008.

Rick Huff, president and CEO of Ainsworth, said: “We made this very difficult decision to permanently close our other two facilities in Minnesota following a review of their ability to be competitive over the longer term. Market conditions since the third quarter of 2008, and the outlook especially for the U.S. housing sector, do not warrant making the additional investments that would be required to make the two mills economically viable.”

Ainsworth is working with affected employees and local authorities to mitigate the effects of the closures. Anticipated cash severance and other employee related costs associated with the closures are expected to be in the range of USD 7 million.

Ainsworth’s three OSB mills in Canada (located at 100 Mile House, British Columbia, Grand Prairie, Alberta, and Barwick, Ontario) which have a combined capacity of approximately 1.6 billion square feet (3/8-inch basis), continue to run at full capacity. Production at the OSB mill in High Level, Alberta, in which the company has a 50% interest, has been indefinitely curtailed.