Largely due to increased success in prevention of mother-to-child transmission, new HIV infections among children globally have declined by 47 percent since 2010, from 300,000 in 2010 to 160,000 in 2016. However, the epidemic continues. In 2016 2.1 million children under fifteen years old were estimated to be living with HIV globally, with 85 percent living in sub-Saharan Africa. Without access to HIV care and antiretroviral therapy (ART), infants and younger children living with HIV are at high risk for mortality, with a mortality rate of about 30 percent by the first year of life and 50 percent by their second year. Therefore, prompt diagnosis and adherence to effective ART is critical. Early infant diagnosis is becoming more widely available globally, allowing for earlier identification of infection close to birth and opportunities to start treatment early in infants and the potential for cure strategies. With effective treatment, pediatric HIV infection has been transformed from a fatal disease to a lifelong chronic disease. Much of pediatric HIV care focuses on co-morbidities related to long-term HIV infection and its treatment. In addition, children living with HIV require close monitoring as they age into adolescence, a high-risk period when they navigate mental, physical, and emotional development. As adolescents become independent from parents or guardians and face choices regarding relationships, sexual behavior, and alcohol and drug use, they are at high risk for poor adherence to ART.