Today the HIV infection is a chronic disease with significantly longer duration of the life of the patients. Problems of pressing interest are the persistent immune activation and chronic inflammation during the treatment with antiretroviral therapy. Taking this into account, different factors which could affect the immune system and the progress of the HIV infection are being researched. Vitamin D (25(OH)D) is one of those factors if we take note of its effect on the innate and acquired immunity. The aim of this study was to assess 25-hydroxyvitamin D (vitamin D) status in one part of the Bulgarian HIV-infected adult population and to assess connection between 25-hydroxyvitamin D (vitamin D) status and plasma levels of some major cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ). The study includes 145 HIV-positive patients, who are being monitored in the Department for acquired immune deficiency at Specialized Hospital for Infectious and Parasitic Diseases “Proff. Ivan Kirov”—Sofia. From all of the monitored patients only in 15% of the tested we found normal 25(OH)D serum levels, and in 12% of the patients we found deficiency. The largest group is that of patients with insufficiency of vitamin D. We didn’t discovered significant difference in the 25(OH)D average values between men and women. There were no significant differences in the average values of the 25(OH)D serum levels when dividing the patients according to their antiretroviral therapy, but after separating the patients by gender, we found that the untreated women had average values of 25(OH)D higher than that of the women treated with EFV. On the next stage of the survey on the 60 HIV-infected patients, who are from the first tested group, we additionally defined the cytokine profile. Our results suggests that increasing 25(OH)D deficiency worsens the damaging of the cellular immune response. The lower levels of vitamin Dare associated with increased levels of IL-6, decreased levels of IL-10, IFN-γ and TNF-α. There’s active immune inflammation when there are reduced 25(OH)D serum levels and it leads to stimulated secretion of the regulatory cytokines and suppression of the Th1 antiviral response. The phase of advanced 25(OH)D deficiency is characterized by parallel depletion of the regulatory and effecter capabilities of CD4 lymphocytes. The recovery of the CD4 lymphocyte pool is difficult because of the lower than average 25(OH)D serum levels, regardless of the conducted antiretroviral therapy.