Nonfatal work-related injury (NFI) rates are 49% higher among oil and gas field workers than among workers in all US industries combined, and these injuries are more severe (the rate of lost workdays in the oil and gas field services industry is 2.8 times that of all US industries combined). We analyzed the 1988 to 1990 incident reports submitted by drilling companies to the International Association of Drilling Contractors, an industry-wide international trade association representing 95% of the world's oil and gas drilling companies. We determined geographic and occupation-specific incidence rates by full-time equivalents, calculated per job category and year. Of the 5,251 reports, 5,218 (99.4%) were of NFI and 33 (0.6%) of fatal work-related injuries (FI). The overall NFI rate was 1.2/100 full-time equivalents and the overall FI rate was 7.5/100,000 full-time equivalents. Reported NFI in US territory was 4 times more common than in non-US territory. Reported FI in US and non-US waters were 4 and 5 times more common than on land, respectively. Three job categories-floormen, roustabouts, and derrick-men-accounted for 74% of the NFI and 64% of FI, with a rate ratio, compared with rates for all other occupations, of 10.5, 8.5, and 7.0 for NFI and 5.0, 9.4, and 4.0 for FI. Among all occupations, the body part most frequently injured was the upper extremity (1,631/5,218 [31%]). The four key NFI types and circumstances identified included the upper extremities “caught in” (857/5,218 [16%]), the back “strained” (592/5,218 [11%]), the lower extremities “struck by” (538/5,218 [10%]), and the lower extremities injured while “slipping” (402/5,218 [8%]). Results of these analyses revealed several high-risk occupations in this industry and identified high-risk activities that can be targeted for further study.