ROC Summary/Abstract Loss of one or both parents can have devastating consequences for children, adolescents, extended families, communities, and nations. Recently, improvements in HIV treatment and prevention have led to dramatic declines in orphanhood. This appears to be the result of combination HIV prevention (CHP), particularly expanded access to highly effective antiretroviral therapy (ART) and declining HIV-related mortality among adults – adults who are often parents. The declines in HIV-related orphanhood proffer substantial benefits to children and youth, families, and their communities. Little is known about how declines in orphanhood among youth may have impacted social and economic factors that influence HIV risk as orphans move into the adolescent and young adult (AYA) years. The Rakai Orphans in Communities (ROC) Study will explore impact, measurement, and policy issues at the intersection of orphanhood, HIV risk among AYA, adolescent social transitions, and family and social context. Impacts include HIV risk and social and economic consequences. Measurement of age at orphaning will be a critical component of this proposal. In several studies, earlier age at orphaning appears to be related to more adverse outcomes. Thus, key issues are estimating the impact of orphanhood on social and behavior risk for HIV and how that impact may change based on the age at orphaning. An under-explored component which we will examine is the economic benefits of CHP weighed against the costs. Using the rich resources of the Rakai Community Cohort Study (RCCS), we will explore the relationship between HIV treatment and prevention, orphanhood, and new HIV infection among AYA. Documenting the impact of CHP on HIV-related orphanhood and the decline HIV risk will guide future investments in HIV treatment and prevention programs and health and social policies for children and youth.