A prospective study of acute injuries from sports and physical exercise was carried out during 1 year in a total population of a municipality with 31,620 inhabitants. Data on exposure were collected: the number of participants in each sport, the hours of participation, and number of weeks in the season per year. The number of injuries was used as numerator and the exposure data as denominator in a formula modified from Chambers for the calculation of population at risk in sports. A total of 571 injuries occurred in 28 different sports: 65% of the injured were males. The majority of the injuries were from soccer: 50% of the males and 27% of the females. Incidence rates in 17 sports are presented. The ranking order differs, when calculating not only the number, but also the exposure. Ice hockey and handball were then found to have the highest risk followed by soccer. Team and contact sports on the whole had the highest rates in both genders. As a group, intercompany players had the highest rate, especially in soccer. The lowest rates were found in individual sports such as downhill skiing, horseback riding, racket sports, and running. Gymnastics, except in school physical education, had no injuries at all. Sprains and strains were diagnosed in nearly half of the cases and the foot and ankle were the most frequent sites. Preventive measures are proposed.