Injuries are an important cause of morbidity and mortality in childhood. Injuries at school account for up to 30% of accident and emergency department attendances in school age children in England and Wales. Routine school reports are a possible source of information on these injuries, but work in other countries indicates that schools under-report injuries to children, making it difficult to estimate incidence. Over a four-week period, children attending an Accident and Emergency Department at a District General Hospital in the West of Scotland as a result of a school accident were compared to those included in routine school incident reports in the area for the same time period. One hundred and forty-eight children were identified as attending the Accident and Emergency Department after sustaining an injury which met the definition of a school accident. This would indicate a rate of injuries resulting in hospital treatment of 47 per 1,000 pupils per year. The prospective data collection identified school under-reporting of accidents requiring hospital treatment of 705%. This information obtained allowed estimation of hospital costs to the NHS. The cost of the Accident and Emergency Department attendances, out-patient treatment and in-patient costs for this group of children was estimated at Pounds 7,715. At this rate, the cost of hospital treatment for school accidents for Argyll and Clyde Health Board is estimated at Pounds 134,760 per year. Applied to the Scottish population, costs would be over Pounds 1.8 million per year. These figures supply the first UK estimates of health care costs of school accidents, and hence assist services in deciding the priority to accord school accident prevention.