Introduction: HLA-B*5701 has been associated with the development of hypersensitivity reactions to abacavir, an inhibitor of HIV (human immunodeficiency virus) nucleoside reverse transcriptase, and slow progression or non-progression of HIV infection. This study aimed to determine the prevalence of HLA-B*5701 positivity in treatment na & iuml;ve people living with HIV (PLWH) and to compare age, gender, CD4+, CD8+ T lymphocyte, and HIV-RNA values of HLA-B*5701 positive people compared to negative people.<br /> Materials and Methods: Between lune 2018 and November 2022, treatment-naive PLWH living with HIV who were followed at the Mersin University Faculty of Medicine Hospital, Infectious Diseases and Clinical Microbiology Polyclinic were included in the study. HLAB*5701, age, gender, CD4+, CD8+ T lymphocyte, and HIV-RNA values at the first admission to the hospital were extracted from the patient files and hospital information system. The positivity rate of HLA-B*5701 and the age, gender, CD4+, CD8+ T lymphocyte, and HIV-RNA values at the first admission of people living with HIV who tested positive for HLA-B*5701 were statistically analyzed compared to those who tested negative. Results: Of 375 patients, 49 (13.0%) were female and 326 (87.0%) were male. Five (1.3%) of 375 patients were found to be HLAB*5701 positive. One of the five patients was female, and four were male, with a mean age of 50.6 +/- 24.6 years. The mean HIV-RNA value of HLA-B*5701-positive individuals was 251.596 +/- 479.232 copies/mL, CD4+ T lymphocyte count was 539.4 +/- 328.7/mu L, and CD8+ T lymphocyte count was 793.2 +/- 392.6/mu L. The mean CD4+ T lymphocyte count was 446.4 +/- 265.3/mu L, CD8+ T lymphocyte count was 1261.1 +/- 832.4/mu L and HIV-RNA value was 815.668 +/- 3.223.024 copies/mL in 370 patients whose HLA-B*5701 tests were negative. Conclusion: In the study, HLA-B*5701 positivity was identified in 1.3% of people living with HIV. Despite the low rate, it is suggested that HLA-B*5701 screening be conducted to prevent hypersensitivity reactions with high mortality. However, further studies are needed for cost-effectiveness analysis in regions with low prevalence.