Mercy killing is usually defined as intentional killing, often by family members or friends, with the stated intent to end perceived suffering. International evidence suggests that mercy kiling typically involves an older man killing his ailing wife. In this study, American cases of mercy killing recorded by the Hemlock Society for the period 1960-1993 were examined. It was found the typical case involved an older women being killed by a man, often her husband, with her poor health as the justification for the killing. A firearm was often used in these incidents. These patterns of mercy killing are consistent with patterns of homicide-suicide among older adults. Future research should seek to understand why women are typically the targets, & men the agents of mercy killing. (44 refs.)