A survey of the prevalence and work relatedness of self reported carpal tunnel syndrome (CTS) among United States (US) workers was conducted. Data from the Occupational Health Supplement (OHS) of the 1988 National Health Interview Survey (NHIS) were searched to identify all CTS cases among US workers. The NHIS was an ongoing questionnaire based survey designed to obtain national estimates of the health status of the civilian population. The identified cases were analyzed to identify the industry and occupation of the cases and work activities contributing to CTS. In the analysis, 170.2 million US adults who ever worked were subdivided into those who worked during the past 12 months (recent workers) and those who did not (nonrecent workers). A nonsignificant difference was observed in the prevalence of self reported CTS in recent workers (1.74%) and in nonrecent workers (1.78%). The overall prevalence of CTS was higher among females than males and among recent workers versus nonrecent workers. Among occupational subgroups, the highest prevalence of self reported CTS occurred among mail and message distributing, health care, and construction workers. Among industry subgroups, repair service, transportation, and construction had the highest prevalence of self reported CTS. About 5% of the recent workers who had prolonged hand discomfort saw a medical practitioner. Of these, 675,000 reported that their problem was called CTS, which represented a prevalence rate of medically called CTS of 0.53%. Over half of the medically called CTS cases were diagnosed as being work related. Regression analysis indicated that the most important risk factors for medically called CTS were repetitive bending or twisting of the hands and wrists (repetitive motion), race, gender, using vibrating hand tools, and age, with the respective odds ratios (ORs) of 5.2, 4.2, 2.2, 1.8, and 1.03. The authors conclude that the OHS/NHIS data are consistent with previous reports which indicate repetitive motion during manual work contributes to the etiology of occupational CTS.