The participants were all noninstitutionalized and were recruited from the street. Results revealed a statistically significant relationship between the frequency of injections and positive HIV-antibody test results and that 104 of the participants were antibody-positive at the time the study began. Self-reported needle-sharing behavior and the use of safe houses (shooting galleries) were also related to infection. Observational data that were gathered using ethnographic techniques identified standard cleaning practices, drug sharing between syringes, and accidental punctures as additional risks of HIV infection for intravenous drug users. Data from detailed interviews regarding values associated with needle use also indicated that interventions focusing on needle cleaning can be effective in this population. 30 references