OBJECTIVE: To determine whether community populations in community popular opinion leader intervention venues showed greater reductions in sexual risk practices and lower HIV/sexually transmitted disease (STD) incidence than those in comparison venues. METHODS: A 5-country group-randomized trial, conducted from 2002 to 2007, enrolled cohorts from 20 to 40 venues in each country. Venues, matched within country on sexual risk and other factors, were randomly assigned within matched pairs to the community popular opinion leader intervention or an AIDS education comparison. All participants had access to condoms and were assessed with repeated in-depth sexual behavior interviews, STD/HIV testing and treatment, and HIV/STD risk-reduction counseling. Sexual behavior change and HIV/STD incidence were measured over 2 years. RESULTS: Both intervention and comparison conditions showed declines of approximately 33% in risk behavior prevalence and had comparable diseases incidence within and across countries. CONCLUSIONS: The community-level intervention did not produce greater behavioral risk and disease incidence reduction than the comparison condition, perhaps due to the intensive prevention services received by all participants during the assessment. Repeated detailed self-review of risk behavior practices coupled with HIV/STD testing, treatment, HIV risk-reduction counseling, and condom access can themselves substantially change behavior and disease acquisition.