Over the past 20 years, the mountain pine beetle (Dendroctonus ponderosae) has caused considerable tree mortality across the Rocky Mountain region of the western United States. Although the operational and cost impacts of dead timber are generally well known in the sawmill industry, there remains a need to better understand the impact of large-scale outbreaks on the industry at local and regional scales. Using an expert opinion survey of sawmill managers and procurement staff, this study quantified the relative importance of various cost and operations factors related to harvesting and processing beetle-killed timber in Montana. Respondents reported an average log supply of trees in the red or gray stage of mortality as 24.5 percent of log supply from 2010 to 2014, but this dropped to 5.8 percent by 2015. Cracking and checking were perceived as having the highest negative impact on log value, while waste in milling and breakage of logs in handling were ranked highest for milling operations. For a typical lodgepole pine stand, the volume estimated as sawlogs showed a 15 percent decrease between green and red stages and a 50 percent decrease between red and gray stages, with most of the volume change moving into the pulpwood category. Total average cost increases from green to gray for logging, loading and hauling, and sawmilling were 43, 46, and 46 percent, respectively. Results generally support known relationships between defects, costs, recovery, and value, with some interesting departures with regard to blue stain and equipment maintenance.