Justifiable homicides are defined by the Uniform Crime Reports as "the killing of a felon by a peace officer in the line of duty or the killing during the commission of a felony of a felon by a private citizen." This analysis used justifiable homicide data for police and citizens compiled from the Comparative Homicide File. This data set permits detailed examination of trends, characteristics, and patterns of justifiable homicides across the United States for the 12-year period of 1976 to 1987, which are the only years covered by the data set. The findings show a general decrease in justifiable homicides, mirroring the trend in criminal homicides for the 12 years under study. Firearms, primarily handguns, were the primary weapons used in justifiable homicides. Justifiable homicides occurred most often, for both police and citizens, during the commission of a crime. This contrasts with criminal homicides, for which the majority occurred during interpersonal conflicts. The majority of both justifiable and criminal homicides involved young males as both perpetrators and victims. African Americans were overrepresented in proportion to their percentage of the population for both criminal and justifiable homicide. Criminal homicides were also primarily intraracial. White involvement in justifiable homicide included many interracial killings. Suggestions for future related research are offered. 3 tables and 32 references