Purpose: The aim of this study was to examine the incidence of musculoskeletal injuries, site and type of injury, and the most common injury diagnoses in young ballet dancers at the Royal Swedish Ballet School, a public school in Stockholm. Methods: This retrospective study of 476 students (297 girls and 179 boys) aged 10-21 years was based on medical records for the period August 1988 to June 1995. Data on diagnosis, site of injury and type of injury were collected, and the injuries were classified as traumatic or due to overuse. Results: In total, 438 injuries were recorded. The injury incidence rate was 0. 8 per 1,000 dance hours in both female and male dancers and tended to increase with increasing age. Most injuries occurred as the result of overuse. Seventy-six per cent of all injuries occurred in the lower extremities. Ankle sprain was the most common traumatic diagnosis, while the most common overuse-related diagnosis was tendinosis pedis. A few gender differences were noted. Conclusions: The findings of this study suggest that there is a need to apply primary injury prevention in young ballet dancers. Future studies could aim to identify (1) injury risk factors and (2) injury prevention programmes that are effective at reducing injury rates in young dancers. Level of evidence: II.