Carpal tunnel syndrome has been reported to occur between two and ten times as frequently in women as in men. It also has been reported that this syndrome is often associated with the performance of certain manual tasks. Such cases can be considered an occupational disease. This study was addressed to the question: Why do some people develop carpal tunnel syndrome while others do not? Two matching female populations, one with a known history of carpal tunnel syndrome and one without a known history of carpal tunnel syndrome, were selected and differences in hand size and work methods were studied. Both populations were employed in the same production sewing jobs. While differences in hand size were not found, use of forceful exertions and of deviated wrists and pinch hand positions — particularly during forceful exertions — were found to be associated with carpal tunnel syndrome.