This 34-page paper represents a compilation of ten programmes that demonstrate their effectiveness in reducing behavioural risks for pregnancy and sexually transmitted infections (STIs), including HIV, among youth in developing countries. The report describes these youth as facing significant threats to their health and well-being as a reault of HIV/AIDS, high rates of STIs, and unintended pregnancies that may result in maternal morbidity and/or mortality. To that end, this paper is the result of a literature review of nearly 200 programmes in developing countries from which the ten programmes are highlighted as showing the successful impact on sexual behaviours and/or on sexual health outcomes. The paper's conclusion, in part, is that in spite of a significant amount of worldwide research changes in knowledge and attitudes alone do not necessarily result in behaviour change. This document is available online at http://www.advocatesforyouth.org/publications/sciencesuccess_developing…