Some chronic mentally ill populations are at high risk for infection with human immunodeficiency virus. The authors argue that stereotypes of the mentally ill as asexual or neutered have bad dangerous consequences, namely the absence of sex education and AIDS prevention as an integral part of treatment. To counter this neglect, the authors developed an AIDS prevention program in a large inner-city mental health center that serves primarily black and Latino patients. Prevention efforts include individual risk assessments and an innovative drop-in group. Central to effective patient education are the distribution of condoms and concrete instruction in their use.