Oil and gas extraction (i.e., removing oil and natural gas from the ground) is a growing industry in the United States, employing approximately 380,000 workers in 2006. In recent years, activity in this industry has increased substantially, from an average of 800 actively drilling rigs in the United States during the 1990s to approximately 1,300 during 2003-2006. In August 2005, the U.S. Department of Labor's Bureau of Labor Statistics (BLS) asked CDC to investigate a 15% increase in fatalities among oil and gas extraction workers (from 85 fatalities in 2003 to 98 in 2004). CDC analyzed data from the BLS Census of Fatal Occupational Injuries (CFOI) for the period 2003- 2006. This report describes the results of that analysis, which indicated that increases in oil and gas extraction activity were correlated with an increase in the rate of fatal occupational injuries in this industry, with an annual fatality rate of 30.5 per 100,000 workers (404 fatalities) during 2003-2006, approximately seven times the rate for all workers (4.0 per 100,000 workers). Nearly half of all fatal injuries among these workers were attributed to highway motor-vehicle crashes and workers being struck by machinery or equipment. Employers should work with existing industry groups and federal, state, and local government agencies to promote seatbelt use. In addition, researchers and public health officials should collaborate with industry groups to establish engineering and process controls that remove workers from potentially dangerous machinery while drilling and servicing oil and gas wells.