Approximately two-thirds of all deaths among children and adolescents aged five to 19 years results from injury-related causes: motor-vehicle crashes, all other unintentional injuries, homicide, and suicide. Schools have a responsibility to prevent injuries from occurring on school property and at school-sponsored events. In addition, schools can teach students the skills needed to promote safety and prevent unintentional injuries, violence, and suicide while at home, at work, at play, in the community, and throughout their lives. The school health recommendations for preventing unintentional injury, violence, and suicide summarized here were developed by the Centers for Disease Control and Prevention (CDC) in collaboration with experts from universities and from national, federal, state, local, and voluntary agencies and organizations. They are based on an in-depth review of research, theory, and current practice in unintentional injury, violence, and suicide prevention; health education; and pubic health. The guidelines include recommendations related to the following eight aspects of school health efforts to prevent unintentional injury, violence, and suicide: a social environment that promotes safety; a safe physical environment; health education curricula and instruction; safe physical education, sports and recreational activities; health, counseling, psychological and social services for students; appropriate crisis and emergency response; involvement of families and communities; and staff development.