The aim of this descriptive cross-sectional study was to describe the prevalence of hypovitaminosis D in a cohort of HIV-seropositive males. Blood samples were collected in November and December 2004 and analyzed in the hospital laboratory. The concentration of 25-hydroxyvitamin D (25(OH)D) was defined as excellent when >75 nmol/l, normal when >50 nmol/l, insufficient when <50 nmol/l, deficient when <25 nmol/l and severely deficient when <12.5 nmol/l. Patient information was extracted from the medical records. A total of 115 males, median age 44 y (range 19-63 y), were included in the study. The median 25(OH)D concentration was 43.0 nmol/l (range 8-163 nmol/l) and the 25(OH)D level was excellent in 13%, normal in 27%, insufficient in 36%, deficient in 20%, and severely deficient in 4% of the cases. Vitamin D level was not associated with age, y with HIV infection, highly active antiretroviral therapy (HAART) or CD4 count. Compared to patients not in treatment, patients on HAART (n = 71) had higher levels of total alkaline phosphatase (median 83.0 vs 75.5 U/l; p = 0.031) and lower, though not significantly, total body mineral density (1.055 vs 1.107 g/cm(2); p = 0.077). This study confirms that the prevalence of hypovitaminosis is high among HIV-infected patients.