Unintentional injuries at school have been identified as a significant public health problem. A major barrier to the development of injury prevention policy has been the absence of national data on the circumstances of injuries to students which occur at school. This study sought to determine the incidence, nature, and circumstances of injuries which resulted in death or hospitalization. Fatalities were identified from national mortality data for 1977-86 inclusive. Coroners' files were then examined to obtain details of the circumstances of injury. Hospitalization cases were identified from the national hospital discharge summary for 1986. Fifteen fatalities were identified. The circumstances of the deaths were diverse with the most frequent event being a fall (n = 4). A total of 1013 first admissions to hospital were identified, giving an overall incidence rate of 152/100,000 students/year. Injury rates declined with increasing age, and males had higher rates than females for all ages. Fractures of the upper and lower limbs and intracranial injury represented more than three-quarters of all injury. The two leading causes of injury, falls, and incidents involving striking against or being struck by a person or object, represented 89% of all incidents. The use of playground equipment and involvement in sporting activity were two of the more common aspects of many injury events. The results suggest that prevention policy should place emphasis on those in their first 2 years of schooling, falls from playground equipment, provision of protective equipment for sporting activities, sporting activities designed to minimize physical contact, establishment of standardized injury referral procedures, first-aid training, and a standardized injury reporting system.