As part of the attention now being paid to prevention efficacy and AIDS program outcome evaluations, there has been growing recognition of the need to target HIV prevention to the unique characteristics and risk profiles of specific populations and to use theory-driven approaches to risk reduction. Drug users, for example, constitute a population of special importance for targeted AIDS prevention. Evidence indicates drug users can and do change their behavior in response to the threat of HIV infection. The most commonly reported changes include increased use of sterile needles, needle exchange programs, bleaching needles to kill the virus, and reducing the number of partners with whom an individual shares needles. The AIDS Community-Based Outreach/Intervention Research program is described as one of the National Institute on Drug Abuse's initiatives to monitor risk factors and behavior and rates of HIV prevalence among injection and crack cocaine users, to evaluate the efficacy of experimental interventions designed to prevent or reduce HIV risk behaviors, and to respond to emerging HIV issues and implement additional interventions to prevent the further spread of HIV. 13 references