Medical insurance claims, linked with work histories for a large automotive manufacturer over a 3-year period, identified large numbers of cases of potentially work-related diseases, including 30,600 episodes of probable cumulative trauma disorders (CTD). CTD incidence rates were calculated within five plants, and high-risk areas identified, however, unknown differences in medical insurance coverage by exposure group limited interpretation. Case-control analyses, with controls also identified by insurance claims, addressed coverage and produced age-adjusted and sex-adjusted estimates of risks. All five plants had departments with statistically significant, elevated risks for one or more of the diagnoses carpal tunnel syndrome, CTD of other upper extremities, rotator cuff syndrome, CTD of the neck and of the lower back. Medical insurance claim data linked with work history provide the basis for practical and comprehensive surveillance for CTD and potentially a variety of other occupational diseases.