A total of 21 consecutive patients who underwent surgery for carpal tunnel syndrome in a regional hospital were analysed for their trade and serum al-antitrypsin phenotypes The majority of these cases were women and mostly manual trades and professions were involved Furthermore, heterozygous antitrypsin phenotypes were more frequent among the surgical cases than among the general Swiss population In a second stage, the incidence of carpal tunnel syndrome in Switzerland was studied for 1 year from June 1988 through May 1989 using the sentinel system developed by the Federal Office of Public Health Administration In all, 188 cases were found, most of whom were women, which was compatible with the frequency in other countries A complementary questionnaire that was filled out by 65 cases and their matched controls showed that housewifes and shop clerks were overrepresented among the patients Likewise, exposure to vibrating tools and frequent extensions and/or flexions of the wrist were mentioned more often by the cases than by the controls The present study confirms previous findings that women are at greater risk of developing carpal tunnel syndrome especially in jobs requiring repetitive movements or operation of vibrating tools A constitutional element in pathogenesis was suggested by observations that the mothers of the cases had often also been afflicted with carpal tunnel syndrome and that the frequency of distribution of antitrypsin phenotypes in patients differed from that in the general population.