The results of operative treatment of 117 patients with carpal tunnel syndrome (CTS) are reported. CTS occurred four to five times more frequently in women than in men. It occurred predominantly in the age group 40 to 60 years. Information on the results of operative treatment and residual complaints were obtained by written inquiry (response: 117/126 = 93%). All patients who were dissatisfied or still had complaints were seen in the outpatient department. The duration of follow-up averaged 15 months: 75% of all patients reported good results. In 89% of the patients the preoperative complaints had disappeared. Dissatisfaction with the operative result was often caused by factors not related to the carpal tunnel syndrome. Factors favouring good results were typical complaints, defined as nocturnal paraesthesias on the volar aspect of the hand and abnormal nerve conduction studies. The results obtained with operation under local anaesthesia in the outpatient department are equivalent to those reported of patients operated in the clinical setting. One-third of the patients felt able to return to work or to resume full normal daily activities within 6 weeks, and 2/3 of the patients within 3 months of the operation.