Background: The prevalence of hypovitaminosis D is variable in the general population, depending on age, gender, sun exposure and geographical area. Hypovitaminosis D has been well described in HIV population.HIV infection and certain ART (anti-retroviral treatment) regimens have been described as independent risk factors causing hypovitaminosis D.The prevalence of hypovitaminosis D in HIV patients is not well known in South America and especially in Argentina. The aim of this study was to determine the prevalence of hypovitaminosis D in a cohort of HIV infected patiens.Methods & Materials: We performed a retrospective review of 1134 subjects followed-up at our center between 2008 and 2016. Patients with vitamin D dosage were analyzed. The prevalence of hypovitaminosis D (insufficiency 30ng/ml -20 ng/ml, deficiency < 20 ng/ml) and the association with efavirenz or protease inhibitor treatment, CD4 lymphocyte count and viral load was analyzed by logistic regression.Results: A sample of 814 patients with at least 1 vitamin D dosage was analysed. Median age was 44 years (r: 21-80), 91.6% were men, 99% under ART, 98.7% had CD4 lymphocyte values greater than 200mm3, and 91.5% HIV-1 ARN less than 200 cop/ml. ART included efavirenz in 40.7% (n = 331) and a PI in 41.03% (n = 334).The prevalence of hypovitaminosis D was 79.7% (n = 649), of which 45.5% had values below 20ng/ml. 79.15% of patients receiving efavirenz and 79.94% of patients receiving PI had hypovitaminosis D. We did not found any association between hipovitaminosis D and efavirenz or PI regimens (p = 0.45 and p = 0.42, respectively). Neither we found an association between hipovitaminosis D and CD4 lymphocyte count or viral load (p = 0.39 and 0.49). Conclusion:The prevalence of hypovitaminosis D among HIV patients was 79.7% in our cohort patients. Approximately 80% of patients receiving both efavirenz and PI experienced hypovitaminosis D, although no significant association was found between antiretroviral therapy and vitamin D deficiency or insufficiency.