The Chicago Women's Health Risk Study, involving more than 2,500 Chicago women during 1995-1996 that came to hospital or health care clinics, identified the factors that signal potential danger of death or life-threatening injury in domestic violence situations. In the great majority of homicides, the woman had experienced violence at the hands of her partner in the past year. The three highest risk factors were the type of past violence, the number of days since the last incident, and the frequency of violence in the past. For a substantial minority of women, about one in five, the fatal or life-threatening incident was the first physical violence they had experienced from their partner. The partner's extreme jealousy was the precipitating factor in 40 percent of the murders of a woman by a man in this situation. The abused women that were killed, and especially those abused women that killed their partners, were much more likely to have sought help, compared to severely abused women not involved in homicide. Most women try to leave an abusive relationship. Leaving can end the violence. When it does not, the continuing violence may become more severe than for women that never tried to leave. A fifth of Latina/Hispanic women reporting a severe or life threatening incident did not seek any help, formal or informal. Women in the study were much more likely to seek medical help or contact the police than to seek counseling or go to a service agency. Abused women that killed their partners had experienced more severe and increasing violence; had fewer resources; and were in more traditional relationships. They were more likely to have called the police after a violent incident against them, compared to any other group of women. Women abused by women intimate partners contacted the police much less frequently than women abused by men, but they were more likely to seek medical care or talk to a counselor. Medical workers and police officers can play important roles in linking abused women to counseling and other community services.