Objectives: The aim of this study was to describe characteristics of perinatally HIV-infected adolescents (PHIVAs), factors associated with mortality, and outcomes at transition. Design: Ongoing observational database collating clinical data on HIV-infected children and adolescents in Asia. Methods: Data from 2001 to 2016 relating to adolescents (10-19 years) with perinatal HIV infection were analysed to describe characteristics at adolescent entry and transition and combination antiretroviral therapy (cART) regimens across adolescence. A competing risk regression analysis was used to determine characteristics at adolescent entry associated with mortality. Outcomes at transition were compared on the basis of age at cART initiation. Results: Of 3448 PHIVA, 644 had reached transition. Median age at HIV diagnosis was 5.5 years, cART initiation 7.2 years and transition 17.9 years. At adolescent entry, 35.0% hadCD4+ cell count less than 500 cells/ml and 51.1% had experience da WHO stage III/IV clinical event. At transition, 38.9% had CD4+ cell count less than 500copies/ml, and 53.4% had experienced a WHO stage III/IV clinical event. Mortality ratewas 0.71 per 100 person-years, with HIV RNA >1000copies/ml, CD4+ cell count less than 500cells/ml, height-for-ageorweight-for-agez-score less than - 2, historyofa WHO stage III/IV clinical event or hospitalization and at least second cART associated with mortality. For transitioning PHIVA, those who commenced cART age less than 5 years had better virologic and immunologic outcomes, though were more likely to be on at least second cART. Conclusion: Delayed HIV diagnosis and cART initiation resulted in considerable morbidity and poor immune status by adolescent entry. Durable first-line cART regimens to optimize disease control are key to minimizing mortality. Early cART initiation provides the best virologic and immunologic outcomes at transition.