The focus of system development was on the incidence of firearm injuries, case fatality rates, demographic data, medical and epidemiological data, the sensitivity of data sources, and the completeness of reporting. The incidence rate of firearm injuries was 45.5 per 100,000 population, and the case fatality rate was 35 percent. Injury rates were highest among adolescents, young adults, males, and blacks. The Medical Examiner and Vital Statistics reported 87 percent and 98 percent of fatal cases, respectively. Passive surveillance of hospital emergency departments identified 72 percent of patients seeking hospital treatment. Among inpatients, 81 percent were identified by medical records. Newspaper clippings were obtained for 31 percent of cases. Information on the victim-perpetrator relationship and the type of firearm was available for 79 percent and 80 percent of cases, respectively. The authors conclude statewide surveillance of firearm injuries using multiple data sources is possible and provides a picture of the overall firearm injury problem. They recommend strategies to enhance computer linkages of medical and police data be pursued to maximize the sensitivity of reporting and minimize surveillance costs. 9 references, 3 tables, and 1 figure