A prospective study was undertaken to determine the annual incidence of trauma to the anterior permanent teeth of children enrolled in the Western Australian School Dental Service. The population comprised 66,500 6-12-yr-old children. 1.66 children and 2.05 teeth per 100 children received trauma. Of the children incurring trauma the incidence per 100 erupted teeth was 11.7. 80.5% of children traumatised one tooth only per incident, but 35% of all teeth that were traumatised involved trauma to two or more teeth. 88% of all traumatised teeth were central incisors. Girls received proportionately more trauma to the maxillary dental arch than did boys. Fracture involving both the enamel and the dentine was the most commonly recorded class of trauma (42.7% of cases). There was no obvious pattern to the overall distribution of trauma through the week or the year. Approximately one-third of all traumata occurred at school, one-third at home, and the remainder elsewhere. Trauma to the maxillary dental arch occurred most frequently at home, while trauma to more than one tooth (multiple trauma) occurred most commonly at school. Trauma incidence resulting from falling or being pushed was almost twice as high among girls as among boys. Bicycle accidents caused a higher than average rate of multiple trauma and of pulpal exposure.