PURPOSE: The HIV Care Continuum highlights the need for HIV-infected youth to be tested, linked, and maintained in lifelong care. Care engagement is important for HIV-infected youth in order for them to stay healthy, maintain a low viral load, and reduce further transmission. One point of potential interruption in the care continuum is during health care transition from adolescent- to adult-centered HIV care. HIV-related health care transition research focuses mainly on youth and on adolescent clinic providers; missing is adult clinic providers' perspectives. METHODS: We examined health care transition processes through semi-structured interviews with 28 adult clinic staff across Adolescent Trials Network sites. We also collected quantitative data related to clinical characteristics and transition-specific strategies. RESULTS: Overall, participants described health care transition as a "warm handoff" and a collaborative effort across adolescent and adult clinics. Emergent transition themes included adult clinical care culture (e.g., patient responsibility), strategies for connecting youth to adult care (e.g., adolescent clinic staff attending youth's first appointment at adult clinic), and approaches to evaluating transition outcomes (e.g., data sharing). Participants provided transition improvement recommendations (e.g., formalized protocols). CONCLUSIONS: Using evidence-based research and a quality improvement framework to inform comprehensive and streamlined transition protocols can help enhance the capacity of adult clinics to collaborate with adolescent clinics to provide coordinated and uninterrupted HIV-related care and to improve continuum of care outcomes.