The Weapon-Related Injury Surveillance System (WRISS) was created with support from the Centers for Disease Control and Prevention to track the epidemiology of fatal and nonfatal weapon injuries and to determine if such a tracking system is feasible and useful. With data available from death certificates and emergency department reports, Massachusetts became the first State to assess the effect of weapon injuries on its population. Using 1994 data, WRISS investigators documented levels of risk across population groups. Investigators first linked death certificates and emergency department reports to identify pre-hospital deaths not captured by emergency department reports and to identify patients who left the emergency department alive but later died as hospital inpatients. In 1994, 1,004 firearm injuries and fatalities were reported to WRISS. Fatality rates were determined based on self-inflicted, accidental, and violence-related injuries. WRISS was a feasible and useful way of evaluating firearm injuries, and emergency department reports were useful in isolating black teenage males as the group at highest risk for gunshot wounds. Linked fatal and nonfatal data sets demonstrated much greater lethality of guns than knives and provided a fuller picture of gun accidents and self-inflicted injuries. The ballistics data set documented that, during the period characterized by dramatic growth in the teenage homicide rate, a concurrent shift in weapon type occurred as the revolver lost ground to the semiautomatic pistol. Public health aspects of weapon injuries and fatalities are discussed. 25 references, 1 table, and 3 figures