Mountain pine beetle infestations have continued at epidemic level in lodgepole pine stands since 1969 in the West Gallatin River drainage. This infestation has increased at about a 1.9:1 buildup ratio annually. Since the outbreak began in 1969, surveys indicate that approximately 22,354 merchantable size trees have been killed with an estimated volume loss of 1,061 MMBF. This is a total of about 27 percent of the merchantable lodgepole pine within areas surveyed. Additional tree mortality and volume loss have occurred, but not all infested areas were surveyed due to land exchange between Big Sky Corporation, Burlington Northern Railroad, and the Forest Service. Operational control of felling and burning, and salvage logging of infested trees was initiated in 1971. This action did little to slow the impetus of the outbreak, because the complete infestation could not be suppressed. The outbreak is expected to continue at epidemic levels in 1974, with an increase in the number of infested trees. A cooperative administrative study between the Northern Region and Intermountain Forest and Range Experiment Station is planned in fiscal year 1975 to determine if silvicultural methods can be used to control mountain pine beetle in mature and overmature overstocked lodgepole pine stands on the Gallatin National Forest.