At the Tampere Research Station of Sports Medicine (TRSSM) a continuous coding system of patient visits was started on March 1, 1985. The registration form contained 25 variables including all essential information about the patient's identification, sports, time of and reason for the visit, physician, examinations, diagnosis, treatment, and possible further measures. To classify and number the diagnosis, a specific classification of sports injuries and diseases was drawn up. The data were stored and analyzed using a DEC-2060 computer at the University of Tampere. During 6 months a total of 814 visits were recorded. The three most common sports were soccer, long-distance running, and orienteering. Competitive athletes totalled 337 (62%); 43 of these were top-ranking athletes. The most common reasons for visits were problems of the knee (266 visits, 33%), ankle (80, 10%), and low back (71, 9%). Knee sprains accounted for 10% of all visits. Problems related to the musculoskeletal system were the reason for 751 (92%) of all visits. Operative treatment was needed by 49 patients (6%). The continuous coding system of patient visits at an outpatient sports clinic showed great advantages as a basic data bank for scientific research, annual statistics, and patient identification and filing. The system described has been adopted as part of the daily routine at the TRSSM.