A prospective study of injuries sustained by first team professional foot-ballers either in training or in competition was undertaken over a 3 year period. These were injuries which resulted in loss of availability for playing. In a total of 27 players, 94 significant injuries occurred resulting in 364 weeks "out of action". 79% of these injuries were sustained in matches. Midfield players suffered the most injuries (39%). A prospective study in Heart of Midlothian Football Club's first team players over a 3 year period 1990-3 revealed that significant injuries resulting in loss of availability for playing occurred in 27 players. The majority of injuries occurred in match play (79%) with the average time "out of action" per player being 13 weeks (overall total = 364 weeks). Midfield players suffered the most injuries (39%) and the most common anatomical site of injury was the thigh followed by the knee. Muscle and ligament injuries were the commonest soft tissue problem. 6% of injuries were skeletal. Players older than 26 years of age appeared to be more prone to injury. No good correlation could be found between the number of games played and increased likelihood of injuries.