Osteonecrosis, also known as avascular necrosis, is chiefly characterized by death of bone caused by vascular compromise. The true incidence of osteonecrosis in HIV-infected patients is not well known and the pathogenesis remains undefined. Hypothetical risk factors peculiar to HIV-infected individuals that might play a role in the pathogenesis of osteonecrosis include the introduction of protease inhibitors and resulting hyperlipidemia, the presence of anticardiolipin antibodies in serum leading to a hypercoagulable state, immune recovery and vasculitis. Hereby we present a series of 13 HIV-infected patients with osteonecrosis. The most common symptom upon presentation was arthralgia. The majority of the patients had received steroids, 9 had developed hyperlipidemia after the introduction of HAART, 8 were smokers and 4 patients were alcoholics. In 2 patients, seric anticardiolipin antibodies were detected. Twelve patients had AIDS and were on HAART (11 were on protease inhibitors). We believe that osteonecrosis should be included as differential diagnosis of every HIV-infected patient who complains of pain of weight bearing joints. Likewise, it seems prudent to rule out HIV infection in subjects with osteonecrosis.