STUDY OBJECTIVE: We describe the epidemiology of emergency department (ED) visits for attempted suicide and self-inflicted injury. METHODS: Data were obtained from the National Hospital Ambulatory Medical Care Survey, a national probability sample of ED visits. All visits for attempted suicide or self-inflicted injury (E950 to E959) during 1997 to 2001 were included in these analyses. RESULTS: During the 5-year period, there were approximately 412,000 annual ED visits for attempted suicide and self-inflicted injury, or 0.4% of all ED visits. The annual visit rate was 1.5 (1.3 to 1.7) visits per 1,000 US citizens. The mean patient age was 31 years, and visits were most common among patients aged 15 to 19 years, at a rate of 3.3 (95% confidence interval 2.1 to 4.4). ED visit rates were higher among female patients (1.7) than male patients (1.3) and among blacks (1.9) than whites (1.5). Visit rates did not differ by metropolitan status or US region. The most common method of injury was poisoning (68%), followed by cutting or piercing (20%). One third of visiting patients were admitted to the hospital, with 31% of admissions going to the ICU. A psychiatric disorder was coded for 55% of visits, with depressive disorder accounting for 34% and alcohol abuse for 16%. CONCLUSION: ED visits for attempted suicide and self-inflicted injury are relatively common, serious, and most frequent among adolescents and young adults. Self-poisoning is the most common method. The high prevalence of psychiatric and substance abuse disorders in this population suggests these issues should be considered during management and disposition.