Seriously mentally ill women at risk for HIV infection (n = 96) participated in structured interviews assessing sexual and substance-use behavior over a 3-month period. The majority of the women (63.5%) did not use condoms. Consistent with the theory of reasoned action, attitudes toward condom use and perceived social norms about safer sex were associated with safer sex intentions. Supplementing variables from the theory of reasoned action with safer sex self-efficacy explained additional variance in safer sex intentions. Greater safer sex intentions were related to both greater condom use and less frequent unprotected intercourse. In addition, less frequent sex after drug use and a less fatalistic outlook were associated with less frequent unprotected intercourse. Life circumstances specific to this population are particularly important to examine to improve the effectiveness of risk reduction interventions for seriously mentally ill women. (Contains 2 tables.)