Inpatient discharges and mortality data were linked to ED data, and police data sources were evaluated to evaluate the sensitivity and beneficial features of the system and its predictive positive value. It was found the ED reporting system captured 82 percent of firearm injuries and 74 percent of reportable sharp instrument wounds from 1994 to 1996. Case reporting by demographic characteristics of the victim was representative and largely complete. Reporting by characteristics of the incident, such as type of gun, was less reliable. Police data were used to augment the system. From 1994 to 1996, ED- treated gunshot wounds dropped 41 percent, from 662 in 1994 to 393 in 1996. Unintentional and self-inflicted gunshot wounds showed no declines. For every firearm-related homicide, 4.7 nonfatal firearm assaults were treated, and 85 percent of self- inflicted gunshot wounds were fatal. The system proved to be timely, flexible, useful, acceptable, and sustainable. 11 references, 2 tables, and 4 figures