A 6-12 months retrospective study is made of HAART utilization in cases of HIV/AIDS patients at Federal Medical Centre, Owo, Nigeria. The objective to evaluate the rational pharmacotherapeutic approach to the management of the retroviral disease. Sixty two (62) antiretroviral drug-naive HIV/AIDS patients, which comprise of (19) 30.65% males with a mean age of 37.15±8.55 years and (43) 69.35% females with a mean age of 35.68±9.75 years case files are reviewed. The data used for this study was extracted from the clinical records of the Hospital. Sixty six percent of the patients are at World Health Organization (WHO) clinical stage III or IV of the HIV disease at initiation of HAART and 35.70% of patients have baseline CD4 cell count ≤50 cells/µL. Stavudine/Lamivudine/Nevirapine is used as HAART first line regimen in 87.10% of the patients while 12.90% are prescribed Stavudine/Lamivudine/Efavirenz due to underlying TB infection. Three (3) patients switched their initial regimen while a patient had her regimen discontinued because of drug adverse effects. Evaluation of 35 patients for therapeutic response after a mean period of 9.07 months shows that, in 82.86% of patients, mean CD4 cell count increased from 96.70 ± 67.90 cells/µL (median 104 cells/µL) at baseline to 267.60 ± 141 cells/µL (median 267 cells/µL). After a mean period of 9.07 months of HAART, there is a significant difference in the change in CD4 count among male and female patients there is no significant correlation between age and change in patients’ CD4 count and within female patients but there is a significant positive correlation between age and change in CD4 count within male patients. It is therefore concluded that rational use of HAART in patients with retroviral disease will lead to significant improvement in most patients’ immunological status and invariably quality of life.