Aim: The aim of the study is to detect effect of zidovudine + lamivudine+ nevirapine (AZT+3TC+NVP) on liver and kidney. Study Design: Sixty-four children age 0 to 5 years attending FMC Umuahia were enrolled for the study in four groups. Place of Study: Study was carried out in Antiretroviral Clinic and Pediatrics Clinic of Federal Medical Center, Umuahia in Abia State, Nigeria from February 2012 to December 2012. Methodology: Fourteen asymptomatic immunocompromised HIV-infected children receiving HAART, AZT+3TC+NVP were in Group A. Thirty-five HIV-exposed children who initially received nevirapine for six weeks and later continued with co-trimoxazole were in Group B. Eight non-immunocompromised HIV-infected children who only received cotrimoxazole were in Group C. Group D had seven normal HIV-seronegative children who served as control for the study. A 2 ml blood was collected from the children, centrifuged to obtain serum which was analyzed in the laboratory for liver function test (AST, ALT) and kidney function test (creatinine, creatinine clearance). Result: Thirty-three (51.6%) of the participants were male while thirty-one (48.4%) were female. ALT was highest in Group A (14.69 IU/L) followed by Group B (13.54 IU/L), Group D (7.77 IU/L) and Group C (6.12 IU/L) respectively. AST was highest in Group A (39.42 IU/L), followed by Group B (32.22 IU/L), Group C (18.66 IU/L) and Group D (14.46 IU/L) respectively. Creatinine was highest among children in Group A (57.17 mu mol/l) followed by Group C (56.49 mu mol/l), Group B (53.06 mu mol/l) and Group D (35.42 mu mol/l). Creatinine clearance was highest in Group A (100.58 ml/min/1.732m(2)), followed by Group D (84.48 ml/min/1.732m(2)), Group C (74.69 ml/min/1.732m(2)) and Group B (61.17 ml/min/1.732m(2)) respectively. The BMI was highest in Group A (32.89 kg/m(2)), followed by Group B (26.33 kg/m(2)), Group C (22.03 kg/m(2)) and Group D (17.34 kg/m(2)) respectively. Conclusion: The study showed that HAART has significant effect on elevation of BMI and serum creatinine.