Résumé : Objective: To assess the adherence to antiretroviral therapy in adolescents infected by HIV since early childhood and to determine its medical and psychosocial determinants. Methods: The study was based on patient interviews to administer 2 adherence questionnaires. The medical charts were reviewed for the record of the latest CD4 counts, viral load, and sociodemographic characteristics. Results: Thirty-two HIV-infected adolescents were enrolled in the study. Only 15 of 32 of them (47%) claimed adherence greater than 95%, whereas 26 of 32 (81%) had a viral load less than 50 copies/mL. The adolescents with an undetectable viral load had a median adherence rate significantly higher than adolescents with virological failure (100 versus 83.5%; P=. 0.01). Among the latter, 5 out of 6 patients acknowledged adherence less than 95% versus 12 of 26 patients with an undetectable viral load. Having forgotten was the main reason reported for skipping medication doses. Fear of being seen while taking the pills differentiated adolescents with adherence less than 95% from the others (79 versus 33%; P=. 0.01). Conclusion: The self-reported adherence rate evaluated by questionnaire was associated with control of the viremia. However, the significance of these rates and the thresholds used have to be interpreted taking into account the characteristics of the drugs as well as the patients' treatment history. The reasons for skipping treatment doses are related to the adolescent process and the representations that the adolescent has of his illness. © 2013 Elsevier Masson SAS.