The authors determined whether psychiatric symptoms and lack of health and/or social services contacts were associated with HIV risk behaviors among a probability sample of homeless women. Women were interviewed regarding socioeconomic indicators, psychiatric symptoms, health and/or social services contacts, and past-year HIV risk behaviors. Overall, 8 percent of the women injected drugs, 64 percent engaged in unprotected sex, and 22 percent traded sex. Multiple logistic regression results revealed that substance abuse was positively associated with injection drug use and trading sex. Homeless women with case managers were less likely to inject drugs. Although barriers to obtaining drug treatment were associated with trading sex, women attending self-help meetings for substance abuse were also more likely to trade sex. Homeless women who are substance abusers are vulnerable to HIV risk behaviors. Risk reduction interventions for homeless women should be implemented through substance abuse and intensive case management programs.