This study presents the results of a three-year (1989-1991) retrospective survey of sports injuries to children and adolescents (5-17 years of age) treated at a sports injuries clinic (Crystal Palace, London). Of the total of 394 injuries, 178 (45.2%) were to females and 216 (54.8%) were to males. In both females and males the frequency of injuries showed a unimodal relationship with increasing age; the peak frequency in females occurred at age 13-14 years and in males at age 15-16 years. Fifty per cent of the injuries (197) were acute, 49.5% (195) were chronic and 0.5% (2) were inconclusive in diagnosis. Most of the acute injuries were muscle/tendon/ligament sprains, strains or contusions (62%) whereas most of the chronic injuries affected articular cartilage, epiphyseal and apophyseal growth plates (53%). Injuries to knees and ankles accounted for 51% of all injuries. The sports responsible for most injuries were characterised by i) explosive and/or high speed movements and/or ii) physical contact with apparatus, equipment or other players.