Background: There is an increasing reliance on neutrophil/lymphocyte ratio (NLR) as a prognostic marker in certain diseases. Observations have suggested the effects of administering highly active antiretroviral therapy (HAART) to human immunodeficiency virus (HIV) patients to be beneficial as well as having its side effects. Hence, this study is designed to examine the relationship of NLR of HAART in the management and disease progression of HIV infection. Materials and Methods: Twenty male white rabbits weighting between 0.8 and 1.8 kg were randomly assigned to five Groups A, B, C, D, and E with four animals per group. Two milliliters of venous blood was aseptically collected before HAART administration and on days 5, 10, 15, and 20 of treatment. Groups B, C, D, and E received graded doses of 15, 20, 25, and 34 mg/kg body weight of the drug combinations (efavirenz, lamivudine, and tenofovir disoproxil fumarate tablets once daily for 20 days). Neutrophil/lymphocyte counts were determined using hematology autoanalyzer. Results: Showed a significant reduction (P< 0.05) in NLR before HAART administration (controls) when compared to administration of HAART at 15, 20, 25, and 35 mg/kg 5 days after drug administration. The same trend was observed in the various groups at 10, 15, and 20 days after drug administration. Conclusion: Administration of HAART has a significant association on NLR.