In recent years, UNICEF has worked together with national and local authorities and civil society partners in a number of countries in Eastern Europe and Central Asia to develop and implement HIV prevention programmes intended to reduce risks and vul¬nerabilities among most-at-risk adolescents (MARA.) This docu¬ment presents programming experiences from seven countries: Albania, Bosnia and Herzegovina (BiH), Moldova, Montenegro, Romania, Serbia and Ukraine. The overarching goal of these programmes has been to promote HIV prevention among MARA and to ensure their integration into national HIV/AIDS programme strategies and monitoring and evaluation frameworks. Specific objectives included: Contributing to the evidence base on the risk profiles of MARAand other vulnerable adolescents; Advocating for protective policy environments ; Building capacity of government and civil society stakeholdersand service providers to support and provide MARA-orientedservices; Piloting and monitoring interventions to reduce the risk and vul-nerability of MARA to HIV. Programmes began by targeting MARA who are at highest risk of HIV infection, including: adolescent injecting drug users (IDU,) adolescents selling sex, and males who have sex with males (MSM,) to prevent risk behaviours (sharing needles and having unprotected sex.) However, it soon became clear that these HIV risks could not be addressed in isolation. Programmes had to also respond to the circumstances that make adolescents vul¬nerable, including living and/or working on the streets, living in institutions or in settlements for displaced persons.