A cross-sectional descriptive study using a questionnaire with mostly closed-ended questions was carried out on 990 pupils and 46 trainee teachers to investigate their knowledge of and attitudes to HIV/AIDS. Pupils in one school were reassessed after a health talk and distribution of a handout. Despite having had no formal sex education, most respondents were reasonably well informed about the transmission of HIV. However, there were many misconceptions about transmission and prevention and 16.9% of pupils were found to possess very little knowledge of HIV/AIDS. Mass media, teachers and health workers were quoted as the main sources of knowledge. It was found that 24.3% pupils and 6.3% of trainee teachers thought there was a cure, and 27.4% of pupils and 14% of trainee teachers thought there was a vaccine to prevent HIV infection. Schools that were rural, private and English-speaking scored better, as did male students and schools teaching science. The necessity of formal sex education was expressed by 98.5% of pupils and all the trainee teachers. The pupils who were reassessed after receiving a talk and handout showed significant improvement in their knowledge and a change in attitude (p < 0.01). The mass media are important in disseminating knowledge on HIV/AIDS in India but due to the lack of inter-personal approaches to the education system, knowledge is inadequate and misconceptions exist.