BACKGROUND: Differences in resources, knowledge, and infrastructure between countries initiating and countries hosting HIV prevention research trials frequently yield ethical dilemmas. Community Advisory Boards (CABs) have emerged as one strategy for establishing partnerships between researchers and host communities to promote community consultation in socially sensitive research. PURPOSE: To understand the evolution of CABs and community partnerships at international research sites conducting HIV prevention trials. METHODS: Three research sites of the HIV Prevention Trials Network (HPTN) were selected to include geographical representation and diverse populations at risk for HIV/AIDS - in Lima, Peru; Chitungwiza, Zimbabwe; and Chiang Mai, Thailand. Data collection included review of secondary data, including academic publications and site-specific progress reports; observations at the research sites; face-to-face interviews with CAB members, research staff, and other key informants; and focus groups with study participants. Rapid assessment techniques were used for data analysis. RESULTS: Two of the three CABs developed new strategies for community representation in response to new studies. All three CABs expanded their original function and became advocates for broader community interests beyond HIV prevention. The participation and input of community representatives, in response to critical incidents that occurred at the sites over the past five years, helped to solidify partnerships between researchers and communities. LIMITATIONS: Rapid Assessment is an exploratory methodology designed to provide an understanding of a situation based on the integration of multiple data sources, collected within a short period of time, without a formal examination of transcribed and coded data. Case studies, as a method, are meant to draw out what can be learned from a single case but are not, in the scientific sense, generalizable. CONCLUSIONS: In developing countries, CABs can be dynamic entities that enhance the HIV research process, assist in responding to issues involving research ethics, and prepare communities for HIV research.