An effective preventative HIV vaccine could be an important prevention tool for high-risk communities in India such as men who have sex with men (MSM) and transgendered individuals (TG). To ensure any prevention technology will be effective, it must be tested in those that will benefit from it most. In order to recruit MSM/TG participants in research, it is important to know about their accessibility and sexual risk behavior for which little information exits. This formative research study, conducted in collaboration with the Population Council, sought to better understand the group dynamics, sexual risk profiles and health care-seeking patterns of the MSM/TG populations to better inform future cohort development for HIV prevention research. With some variation among research sites, results revealed that multiple factors increase MSM/TG’s vulnerability to HIV infection. Strong social networks (MSM), membership in organized community households (TG) and a high awareness of and access to HIV prevention services indicate potential opportunities for outreach and information about AIDS preventive research studies. To engage MSM and TG communities in HIV prevention research initiatives, it will be essential to work with peers and NGO’s (MSM) and gurus and CBO’s (TG).