BACKGROUND Hematologic abnormalities are among the most common complications of infection with Human Immunodeficiency Virus. These abnormalities are due to: impaired hematopoiesis, immune mediated cytopenias and altered coagulation mechanisms. Anemia is the most frequent,however, leukopenia, lymphopenia, and thrombocytopenia have also been observed. The aim of the study was to find the prevalence of anemia in patients attending anti-retroviral therapy at a tertiary care center of Nepal. METHODS The study was a descriptive cross-sectional study conducted from August 2018 to August 2019 in patients attending anti-retroviral therapy at a tertiary care hospital. Ethical approval was obtained from the Institutional Review Board of National Academy of Medical Sciences before starting the study (Reference number 267). Convenient sampling was used for this study. Data were analysed using the Statistical package for Social Sciences version 20. Point estimate at 90% confidence interval was calculated along with frequency and proportion for the binary data. RESULTS The prevalence of anemia among patients attending anti-retroviral therapy centers in our study was found in 29 (58%) (46.55-69.45 at 90% Confidence Interval). Out of those patients, 20 (63%) were male and 9 (50%) were female. The mean hemoglobin value was 11.946±2.51g/dl. CONCLUSIONS The prevalence of anemia among patients attending antiretroviral therapy in our study was found to be high which is consistent with the findings of other similar international studies. These patients should be routinely monitored and treated for the occurrence of hematological abnormalities.