OBJECTIVE To describe the alterations in the bone metabolism of HIV-seropositive patients and evaluate the effects of antiretroviral therapies. METHODS Cross-sectional analytical study. METHODS A total of 142 subjects (113 male, 29 female), aged 20-45 years were divided into four groups: group A, 33 HIV-seropositive antiretroviral-naive patients; group B1, 36 HIV-seropositive patients on antiviral therapy for over 1 year, without protease inhibitors (PI); group B2, 42 HIV-seropositive patients on combined therapy containing PI for over 1 year; and group C, 15 healthy, HIV-seronegative subjects. Bone mineral density (BMD) were determined by dual energy X-ray absorptiometry in total body, lumbar spine and proximal femur; and evaluation of serum osteocalcin, d-pyridinoline, parathyroid hormone (THP), calcium and phosphate, and urine calcium. RESULTS BMD was significantly lower in HIV-seropositive patients in comparison with healthy controls, in all sites studied. However, no statistical differences were observed among all groups of HIV-infected patients, independently of the antiretroviral therapy. There was a significantly higher occurrence of osteopenia and osteoporosis in HIV-infected patients in comparison with controls (P < 0.0001), with no differences among treatment-naive patients and either of the treatment groups. Bone formation and resorption markers were similar among all studied groups. There was a significant correlation in all bone sites between time of infection and BMD (P < 0.02). CONCLUSIONS BMD was significantly lower in HIV-seropositive patients in comparison with controls in lumbar spine, proximal femur and total body, without significant differences among treatment-naive patients and either of the treatment groups. Only time with HIV infection and not specific therapy was associated with BMD decreases.