Background: Our goal was to evaluate immunologic profile differences of HIV-infected children on antiretroviral treatment (ART). Patients and method: We studied 23 HIV-vertically infected children: a) N-A1 group: 10 HIV-infected children in A1 category; b) N-B2 group: 6 HIV-infected children in B2 category, and c) N-C3 group: 7 HIV-infected children in C3 category. We also studied 13 healthy age-matched HIV-negative children as controls. Cell proliferation was evaluated by incorporation of [3H]-Thymidine. The cytokine production in culture was quantified using commercially available specific ELISA assays. T-cell subsets were determined by flow cytometry. Results: Stimulation indexes of PHA, PWM, and anti-CD3+ anti-CD28 in N-A1 group were higher than in N-C3 group. In unstimulated PBMC, TNF-alpha production of HIV-infected children was higher than the control group (p < 0.05). However, in stimulated PBMC, TNF-alpha production in N-B2 and N-C3 groups was lower than the control group (p < 0.05). In HIV-infected children, CD8+ CD45RA+ CD62L+ T-cells were significantly lower (p < 0.01) and CD8+ CD45RO+ T-cells were higher (p < 0.05) than the control group. Moreover, in NA-1 group, CD4+ CD45RA+ CD62L+ T-cells were higher, and CD4+ CD45RO+ and CD8+ CD45RO+ T-cells were lower, than in N-B2 and N-C3 groups (p < 0.05). On the other hand, CD45RO+, CD45RO+ CD38+, HLA-DR+, CD38+ HLA-DR+ and CD38+ CD4+ and CD8+ T-cells were higher in N-C3 group than the N-A1 and control groups, except for CD4+ CD38+ T-cells. Activated CD8+ T-cells in N-A1 group were higher than in control group (p < 0.01). Conclusion: Our data demonstrate that in spite of ART, there still remain important differences in the immunologic status of HIV-infected children depending on the HIV-infection stage.