Estimates of ambrosia beetle damage on 10 log grades, commonly used in sawmills of coastal British Columbia, were determined by the sawmill team of an Ambrosia Beetle Task Force during 1990–1992. A total of 417 ambrosia beetle attacked logs were evaluated in eight cooperating sawmills. Test logs were processed into lumber products, graded, and valued. Estimates of dollar loss per cubic metre for various log diameter classes were made. The average losses for the 10 log grades with respect to grade of lumber, with and without pinholes, ranged from $3.27 to $77.40/m3of log. Changes in sawing patterns as a result of ambrosia beetle infestation were also assessed. The loss of deep clear potential on high-grade logs increased value losses by 57%. One third of large pulp logs were sawn for lumber. Ambrosia beetle infestation of sawn large pulp logs resulted in $19.20/m3degrade loss.