A prospective study of injuries encountered during participation in a summer soccer camp for youths aged 6 through 17 years revealed an injury incidence of 10.6 per 1000 hours for girls (107 injuries in 458 girls) and 7.3 per 1000 hours for boys (109 injuries in 681 boys). For both sexes, the incidence of injury increased at age 14 years. One certified athletic trainer (W.D.C.) assessed and documented all injuries during the course of the study. Seventy percent of injuries involved the lower extremities. Contusions represented 35.2%, strains 27.8%, sprains 19.4%, and fractures and dislocations 2% of all reported injuries. The ankle was the most frequent site of injury in both sexes. Quadriceps strain was a common injury in boys. The boys with the highest incidence of injury were tall (greater than 165 cm) and had a weak grip (less than 25 kg), suggesting that skeletally mature but muscularly weak boys may be more susceptible to injury while playing soccer with peers of the same chronological age.