Context: The magnitude of firearm-related deaths is known, but few studies ha ire evaluated the magnitude and epidemiology of nonfatal firearm-related injuries. The circumstances resulting in fatal versus nonfatal injury are likely very different. No single data source provides complete details on nonfatal shootings. Objective: To establish a surveillance system to define the epidemiology; of fatal and nonfatal firearm-related injuries. Design: Data were collected on fatal and nonfatal firearm-related injuries that occurred in 1995. Setting: State of Oklahoma. Participants: Medical Examiner, Vital Statistics, hospital emergency and medical records departments, police departments, newspaper clipping service. Main Outcome Measures: Incidence rate of firearm-related injuries; case-fatality rate; demographic, medical, and epidemiologic data; sensitivity of each reporting source; completeness of reporting. Results: The incidence rate of firearm-related injuries was 45.5 per 100,000 population. The case fatality rate was 35%. Injury rates were highest among adolescents, young adults, males, and African Americans. The Medical Examiner and Vital Statistics reported 81% and 98% of fatal cases, respectively. Passive surveillance of hospital emergency departments identified 72% of patients seeking hospital treatment. Among inpatients, 81% were identified by medical records departments. Newspaper clippings were obtained for 31% of cases. Information on the victim-perpetrator relationship and the type of firearm was available for 79% and 80% of cases, respectively. Conclusions: Statewide surveillance of firearm-related injuries using multiple data sources is possible and provides a picture of the overall firearm-related injury problem. Strategies to enhance computer linkages of medical and police data should be pursued to maximize the sensitivity of reporting and minimize the costs of surveillance.