The spectrum of children's head trauma, excluding that caused by motor vehicles and child abuse, was investigated by examining 197,561 injuries treated in hospital emergency rooms during 1978. Such injuries accounted for 11 per cent of emergency-room visits. Preschool children had the highest rate of head injury, and among infants under one year these injuries accounted for 40 per cent of the total injuries treated in emergency rooms. Concussion occurred in one-fifth of adolescent cases. Fractures occurred in a relatively small percentage, but infants under one year had the highest rate (6 per cent). Most injuries to younger children occurred at home; among older children they occurred most often during sporting or recreational activities. The implications of these findings for preventive efforts are discussed.