This article reports the results of a study involving the Centers for Disease Control and Prevention and the U.S. Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS). Data were obtained from June 1, 1992, through May 31, 1993 using NEISS. National estimates are presented, based on data from a representative sample of U.S. hospitals, on the number and characteristics of persons with nonfatal firearm-related injuries treated in hospital emergency departments. National estimates of all nonfatal gun- related injures treated in emergency departments are presented first, followed by more detailed national estimates of the number and characteristics of nonfatal firearm-related injuries. Data are compared with prior estimates obtained from earlier studies. Results indicate that an estimated 99,025 persons were treated for nonfatal firearm-related injuries in U S hospital emergency departments during the study period. The rate of nonfatal firearm-related injuries treated was 2.6 times the national rate of fatal firearm-related injuries for 1992. The analysis concludes that nonfatal firearm- related injuries contributed substantially to the overall public health burden of firearm-related injuries. Additionally, although NEISS is useful to monitor the number of nonfatal firearm-related injuries in the United States, the limitations of NEISS are noted. The authors recommend the development of a national surveillance system to provide uniform data on firearm-related morbidity and mortality for use in risk factor research and firearm- and violence-related intervention programs. Tables, references