Background-Little is known about hospitalization in African adolescents with perinatally acquired HIV (PHIV+ adolescents). We described the incidence and causes of hospitalization in participants enrolled in the Cape Town Adolescent Antiretroviral Cohort in South Africa.Methods: Data collected from July 2013 through October 2018 from PHIV+ and HIV− adolescents were analyzed. Participants were assessed every six months and data on intercurrent hospitalization were abstracted. Causes of hospitalizations were classified according to ICD-10 codes. Descriptive statistics, time-to-event analysis and Poisson regression were used to describe causes and incidence and to determine incidence rate ratios for factors associated with hospitalization.Results: 515 PHIV+ and 109 HIV− participants had a median follow up of 4.1 years (IQR: 3.7-4.6). At enrollment HIV+ participants had a median duration of ART of 7.6 years (IQR:4.6-9.2), median CD4 count of 713 cells/mm 3 (IQR: 561.0-957.5) and 387 (75%) had a viral load <50 copies/ml. There were 149 hospital admissions over 64-months. Crude incidence rates for hospitalization were 6.6 (95%CI: 5.7-7.8) and 2.2 (95%CI:1.2-4.3) per 100-person years (p=<0.01) in HIV + and HIV− respectively.Ninety of 149 (60%) admissions in HIV+ participants were classified as non-infectious, 36/149 (24%) were infectious, and 23/149 (16%) were 'other HIV-related' or 'unknown'. Older age (15-19 years) and maintaining a CD4>500 cells/cm 3 were associated with decreased risk of hospitalization: adjusted incidence rate ratios of 0.61 (CI: 0.44-0.86, p=<0.01) and 0.68 (CI: 0.49-0.94, p=0.02), respectively.