As Cambodia was returning to peace in the early 1990's, HIV/AIDS reached the war-torn Kingdom. With around 3.5% of the adult population aged from 15 to 49 already infected, the Kingdom of Cambodia is facing today the highest rate of infection in Asia. The epidemic has begun to move from vulnerable groups into the general population in the city, towns and rural and remote areas. The Strengthening HIV/AIDS/STDs Prevention Education Programme for Secondary Schools in Cambodia was supported by UNESCO Cambodia in collaboration with the School Health Department of the Ministry of Education, Youth and Sports and was funded by the World AIDS Foundation and UNFPA. A series of training for teachers and students in secondary schools was conducted in 1998 up to 2000. In order to evaluate the achievements and effectiveness of the programme, a medium-scale research project was designed and implemented in eleven selected provinces, which covered urban, rural and remote secondary schools in the Kingdom of Cambodia. It is the first time that this kind of research is conducted in the Cambodian education system, with the use of scientific methods and sophisticated design to acquire the most accurate information. The primary purposes of the research were to assess the effectiveness of the project, and to provide recommendations for further improvement of the HIV/AIDS/STDs Prevention Education programme, especially the learning and teaching methodology. The secondary purpose was to build the capacity of governmental staff of the School Health Department in both research and statistical analysis.This report summarises the quantitative and qualitative findings from testing and interviewing the target population in secondary schools: students of grade 9 and the upper grades, school directors, parents and teachers and trainers of HIV/AIDS/STDs prevention education.