A multistage sampling survey to measure annual and cumulative mortality of lodgepole pine by mountain pine beetle was conducted on the Beaverhead and Gallatin National Forests, 1978-79. The survey area, 270,000 acres, was stratified into three intensity classes from aerial sketchmapping. This was followed by large scale (1:6,000) aerial photography, photographic interpretation, and ground truth measurements. Estimates of the number of lodgepole killed by mountain pine beetle in 1977 were 1,270,617 trees and 24.2 million cubic feet. The number of total standing dead within the survey boundaries was estimated at 3,117,888 trees and 62.2 million cubic feet. This total standing dead represents 31.4 percent of the total basal area.