BACKGROUND: Symptomatic human immunodeficiency virus (HIV) infection during late childhood and adolescence may be an emerging problem in southern Africa, but it is one that is poorly described. We investigated social and clinical features in patients of this age group presenting to a HIV treatment clinic with special adolescent services in Harare, Zimbabwe. METHODS: All patients aged 8-19 years and their guardians who attended an adolescent HIV treatment clinic were asked to consent to an interview and a review of medical notes. RESULTS: Of 32 patients, 17 (53%) were male. The median CD4 cell count at presentation was 101 cells/microL (interquartile range, 35-197 cells/microL). Sixty-two percent experienced stunting (mean Z score for height-for-age, -2.55; 95% CI, -2.00 to -3.10), and all presented with World Health Organization stage 3 or 4 HIV infection. The median age at the first HIV test was 11 years, with a median of 3.5 years delay since the first HIV-related illness. Recurrent respiratory tract infections, skin complaints, diarrhea, and past tuberculosis were the most common HIV-related complaints. Seventeen patients (55%) were double orphans, and 10 (62%) surviving parents were known to be HIV positive. CONCLUSIONS: In this small study, HIV-infected adolescents were profoundly immunosuppressed, with characteristics suggesting long-standing HIV infection. The equal sex distribution and high incidence of parental and sibling mortality were consistent; the majority of children had HIV-infected parents and, therefore, were potentially long-term survivors of HIV infection due to mother-to-child transmission. Greater recognition of the substantial burden of undiagnosed HIV infection and acquired immunodeficiency syndrome in this age group is needed, together with services aimed at reducing barriers to earlier diagnosis and initiation of treatment.