At treatment entry, patients completed self-report questionnaires on AIDS-related knowledge and sexual and drug use practices. There was a high rate of understanding of risk associated with drug use and perinatal transmission of HIV. Knowledge of high-risk sexual behavior varied, and knowledge of the medical consequences of HIV was modest. Engagement in several high-risk behaviors was identified: lack of condom use, intravenous drug use, sharing of needles, sex with an injecting drug user, and exchanging sex for money or drugs. AIDS-related knowledge and engagement in high-risk behaviors were not significantly correlated. The finding that increased knowledge was not associated with decreased risk behavior concurs with that of other investigators. Des Jarlais and Friedman advocate providing a means for behavioral change (e.g., provision of free treatment slots, provision of bleach for sterilizing equipment) and providing sustained reinforcement for risk-reduction behaviors. Fisher and Fisher found that interventions that were conceptually based and group-specific and that provided information, motivation, and behavioral skills had the most impact on risk-reduction behavior. These approaches need to be developed and tested in this high-risk population. 3 tables and 36 references