Behavioral, physiological and socio-cultural factors make young people more vulnerable than adults to HIV infection. This report provides a regional overview of adolescents' knowledge of HIV/AIDS and behaviors in Sub-Saharan Africa that put them at risk for or protect them from infection. It also examines the social and economic context of adolescents' lives. All of these factors are fundamental to understanding the progression of the epidemic in Sub-Saharan Africa. In addition, knowing the risk and protective behaviors identified in this report, which are generally not monitored by surveillance systems that track HIV/AIDS levels and trends, is essential for guiding the efforts of policymakers and providers of health information and services to young people - at both the regional and the country levels.