BACKGROUND: Rural Indian tribes are anthropologically distinct with unique cultures, traditions and practices. Over the years, displacement and rapid acculturation of this population has led to dramatic changes in their socio-cultural and value systems. Due to a poor health infrastructure, high levels of poverty and ignorance, these communities are highly vulnerable to various health problems, especially, communicable diseases including HIV/AIDS. Our study sought to assess knowledge, attitudes and practices regarding sexuality, and the risk factors associated with the spread of HIV/AIDS and STDs among these communities. METHODS: A nested cross sectional study was undertaken as part of the on going Reproductive and Child Health Survey. A total of 5,690 participants age 18-44 were recruited for this study. Data were obtained through home interviews, and focused on socio-demographics, knowledge, attitudes and behaviors regarding sexuality, HIV/AIDS and other STDs. RESULTS: The study revealed that only 22% of adults had even heard of AIDS, and 18 % knew how it is transmitted. In addition, only 5% knew that STDs and AIDS were related to each other. AIDS awareness among women was lower compared to men (14% vs.30 %). Regarding sexual practices, 35% of the respondents reported having had extramarital sexual encounters, with more males than females reporting extramarital affairs. CONCLUSION: Lack of awareness, permissiveness of tribal societies for premarital or extra-marital sexual relationships, and sexual mixing patterns predispose these communities to HIV/AIDS and STD infections. There is a dire need for targeted interventions in order to curtail the increasing threat of HIV and other STDs among these vulnerable populations.