A study of the risk of developing cumulative trauma disorders (CTDs) was conducted to evaluate workers' compensation claims as a means of identifying workplaces at high risk of CTDs. All claims filed with the Ohio Bureau of Workers' Compensation over the period 1990 through 1984 were reviewed to identify CTD cases. Incidence rates for CTD were computed. The data were analyzed to determine industries and occupations with the highest risk of CTD. A total of 6849 cases of CTD originating from 3242 employers were identified. Tenosynovitis due to continuous motion was the most frequent diagnosis, accounting for 58.3 percent of the cases. The wrist was the most frequently affected body part, accounting for 48.4 percent of the cases. Women had consistently higher incidence rates for CTDs than males for all age groups. The highest rate for females occurred in the 36 to 45 age group. The overall incidence rate for CTDs was 4.1 cases per 10,000 workers for females and 2.3 cases/10,000 for males. The annual number of CTD cases reported increased nearly threefold between 1980 and 1984. This increase was due primarily to increases in cases of tenosynovitis. Approximately 40 percent of the lost workdays was due to injuries resulting in 30 to 60 days disability. The highest rates (in cases/10,000) of CTDs occurred in the manufacture of transportation equipment (17.7), furniture (12.8), leather articles (12.4), electronic and electric equipment (11.8), rubber products (11.6), and food products (11.3). Over 60 percent of the cases occurred among fabricators, assemblers, machine operators, and miscellaneous machine operations. The authors conclude that analyzing workers' compensation claim data is an effective surveillance method for identifying occupations posing a high risk of CTDs.