The study recruited 579 individuals in two towns, one of 50,000 and one of 10,000 population. The following approaches to intervention were tested: (1) an intensive outreach program using indigenous outreach workers who provided reinforcement of an HIV risk reduction program; and (2) a low-intensity outreach program combined with a more intensive office-based HIV risk reduction program. Both approaches were compared with the National Institute on Drug Abuse (NIDA) recommended standard intervention. The enhanced interventions reduced HIV risk taking reported by study participants. Both the intensive outreach combined with office intervention and the intensive office intervention without outreach reinforcement significantly reduced sexual risk taking by active drug users, beyond the reductions reported for the NIDA standard program. Enhanced risk reduction programs produced differential impacts for males and females between high- and low- intensity outreach models. 23 references, 3 notes, and 5 tables