Injuries remain the leading cause of death of Americans ages 1 to 44 years, and prevention is an essential companion to injury treatment. Effective injury prevention begins with an understanding of epidemiologic issues, such as injury classification, demographic patterns, data sources for research, and general prevention strategies. Emergency physicians can help to reach national goals for injury prevention, as outlined in Healthy People 2010, through patient education, surveillance system enhancement, and ongoing research in treatment and outcomes. Interventions for certain injury problems, including violence, falls, traffic injuries, and alcohol abuse, can be implemented in emergency departments. Although great progress has occurred in injury prevention in the United States, physicians have an integral role in ongoing efforts, through patient education, use of social resources, design of intervention programs, research, and policy development.