Objective: The study was aimed to evaluate the relationship between pharmacy supply, self-reported treatment adherence and HIV viral load in HIV-infected children. Methods: A retrospective (52 weeks) cohort study was conducted through the review of the existing databases. Pharmacy supply was classified as “home delivery” when the medications were delivered home and as “in pharmacy pick-up” when they were picked up at the pharmacy. Adherence was assessed through retrospective (3 days recall) self-report. Fisher’s exact model, univariate and multivariate logistic regression analyses were used. Settings: The study collected data on 140 HIV-infected children (13 years) were significantly less likely to reach undetectable viral loads than children under 13 years (odds ratio 0.38; 95% CI 0.16 to 0.89). Conclusion: In our study, pharmacy supply was not associated with self-reported adherence. Most importantly, adherence and age were significant predictors of reaching undetectable viral loads.