To study the epidemiology of deaths involving firearms kept in the home, we reviewed all the gunshot deaths that occurred in King County, Washington (population 1,270,000), from 1978 through 1983. The medical examiner's case files were supplemented by police records or interviews with investigating officers or both, to obtain specific information about the circumstances, the scene of the incident, the type of firearm involved, and the relationship of the suspect to the victim. A total of 743 firearm-related deaths occurred during this six-year period, 398 of which (54 percent) occurred in the residence where the firearm was kept. Only 2 of these 398 deaths (0.5 percent) involved an intruder shot during attempted entry. Seven persons (1.8 percent) were killed in self-defense. For every case of self-protection homicide involving a firearm kept in the home, there were 1.3 accidental deaths, 4.6 criminal homicides, and 37 suicides involving firearms. Hand-guns were used in 70.5 percent of these deaths. The advisability of keeping firearms in the home for protection must be questioned.