With 16 Cooperative Agreement sites presently funded, America's Midwest population remains underserved in HIV prevention efforts even though CDC data indicate significant rates of HIV/AIDS in Midwest cities. St. Louis, a metropolitan area with 15.3 AIDS cases per 100,000 and high rates of HIV risk behaviors, lacks intervention services which makes it fertile ground for an intervention study. Building upon established city-wide collaborations, the investigators propose surveillance of the spread of HIV among out-of-treatment drug users and the implementation and evaluation of a peer-oriented program aimed at reducing HIV risk. The proposed new study, called EachOneTeachOne, follows the guidelines of the NIDA Cooperative Agreement. The Epidemiological Aims include assessing among out-of-treatment IDU and crack cocaine users recruited from two target areas: a) HIV seroprevalence; b) prevalence of HIV risk behaviors; c) prevalence of tuberculosis, hepatitis B and syphilis which have similar risk factors as HIV and are markers for the spread of HIV; d) stages of change; e) characteristics of peer networks, and f) symptoms of depression and antisocial personality disorder. The Evaluation Aims involve testing the efficacy of an enhanced peer- oriented intervention compared to a standard intervention for reducing HIV risk behaviors at a six month follow-up. Analyses will include: a) a contrast of the enhanced intervention to the standard on reduction of HIV high-risk behaviors, peer network characteristics and stages of change, controlling for race and gender, and b) the association of depression and antisocial personality with these behaviors. To accomplish these aims the investigators will: a) define two areas of St. Louis which are at highest risk for IDU and AIDS as evidenced by DUF, DAWN, police arrest data, and public health reports of the prevalence of hepatitis B, syphilis, tuberculosis, HIV infection and AIDS; b) recruit 50 out-of-treatment IDU and crack cocaine users per month for 24 months through street outreach orchestrated from two St- Louis City Health Department satellite health centers, known as HealthStreet, which will be located at the centers of the two areas; c) provide a standard HIV risk reduction intervention to 35 eligible subjects per month out of the 50 recruited; d) provide the enhanced intervention, in addition to the standard, to a minimum of 21 subjects per month randomly selected from the 35 recruited subjects; the enhanced program, which has been designed to consist of a 4-week series called "Structured Chemical Free Experiences", will be cofacilitated by drug treatment program graduates and community professionals, and e) conduct a six-month follow-up assessment similar to the baseline on at least 85% of the randomized subjects. Outcome measures will include changes in HIV risk behaviors, alcohol and drug use and problems from drug use, incidence of HIV, stages of change, peer network characteristics, and symptoms of depression and antisocial personality disorder.