Abstract Successful conduct of any HIV vaccine trial (HIVVT) requires a high level of preparedness in the community. A cross-sectional study was conducted in Tamilnadu, India among 501 participants from six different risk groups to investigate their willingness to participate (WTP) in future preventive HIVVTs and to explore their knowledge and attitude toward preventive HIV vaccines. In total, 82% were willing to participate and the desire to be protected from HIV was the main reason for WTP. Perception of not being at risk was the major reason for refusal among married women. The knowledge scale showed a significant increase in scores after vaccine education. In all, 76% revealed the hope that there would be an effective vaccine in a few years and 71% hoped that the HIV vaccine would protect them from HIV infection. The main concern was the unknown efficacy of the vaccine (50%) and the effects of an HIV vaccine on participants' lives (51%). Overall, 76% agreed that sex without a condom would not be safe whether or not there was an HIV vaccine. To conclude, it is likely that high-risk volunteers will be willing to enroll in preventive HIVVTs. Addressing barriers and concerns by providing information through appropriate agencies will spell out success for preventive HIVVTs in India.