The present study compared battered women incarcerated for killing/seriously assaulting their abusers with battered women incarcerated for other offenses to explore possible similarities and differences in the characteristics and experiences of the two groups as well as to determine what factors may lead some battered women to use lethal force against their partners. Comparisons were made on a number of variables including sociodemographic factors, characteristics of the battering relationship, alcohol/drug use of battered women and their abusers, perceived social support, actions taken to end the violence, prior criminal behaviors, and childhood trauma factors. Findings revealed that women in the homicide/assault group were older, in the relationship longer and experienced a longer duration of violence in this relationship. They also experienced more frequent and severe battering, including sex assaults and sustained more injuries than those in the comparison group. Further, battered women who killed/seriously assaulted their partners were more likely to believe that their lives were in danger, were less likely to use violence against their partners, and were less likely to have a prior criminal record or to have served time previously. The implications of the findings are discussed.