This study will contribute to a better understanding of factors that influences school-based adolescent HIV/AIDS prevention. A broader perspective and better understanding on the importance of teachers’ role and the cultural context, will meet the needs that have been formulated by a number of agencies and authors. The study will be an integrated part of a large-scale, school-based adolescent HIV/AIDS preventive EU-funded research project (SATZ) taking place in South Africa and Tanzania, and it represent s a unique opportunity to investigate the associaiton between teachers' and students' perceptions and outcomes.Data for the study will be collected through two periods of fieldwork using in-depth interviews with school teachers; in 2004 and the second p eriod in 2005. Funds for fieldwork in Polokwane (2004) have been secured through GLOBINF, the Centre for Prevention of Major Global Infections at the University of Oslo. The second field work period is planned in collaboration with the University of Cape Town from April to June 2005. Data on students’ behavior and opinions will be collected through the first follow-up survey among approx. 15.000 students at 90 schools in Tanzania and South Africa. Finally, data will collected through a teachers' survey th at will be conducted with all teachers at the control- and intervention schools in the SATZ project. This survey will be implemented in both Tanzania and South Africa. Data analysis will include a number of analytical approaches as both qualitative and quantitative data are collected. Throughout the planning period, the implementation and while analyzing data, the present study will make benefit of the strong relations within the project between leading African and European researchers in this field. This study will provide important new information concerning how teachers exercise their influence through school-based HIV/AIDS prevention programs.