Individuals at the study clinics will undergo a screening survey and HIV counseling and testing; they will return to the clinic to receive their HIV test results, post-test counseling, and further screening. Those who are HIV uninfected, meet preliminary eligibility requirements, and are willing to participate will be enrolled as index participants. Each index participant will be asked to identify and attempt to recruit at least two other people (potential network members) whom he/she has had sex with or taken drugs with in the 3 months prior to screening. Infected and uninfected network members will be eligible for enrollment. Index participants will be randomly assigned with their network members to either the intervention group or a control group. All participants will receive HIV counseling and regular HIV testing. Index participants assigned to the intervention group attend six, two-hour peer educator-training sessions over a period of 4 weeks. The training sessions focus on skills building and promotion of risk-reducing behaviors. A one-hour booster training session is held for index participants after their 6- and 12-month follow-up assessments.