Articular manifestations were observed in 10 patients (8 men, 2 women, aged from 23 to 46 years) with human immunodeficiency virus (HIV) infection. All men were homosexuals, except for an intravenous drug addict. One woman was a native of Gabon and the other had multiple transfusions. The joint diseases were of the polyarthritis and acute oligoarthritis types, affecting mainly the knees and ankles but also the wrist and fingers; the spine was involved in one case. The synovial fluid present in 4 patients contained 5,000 to 27,000 cells per cubic millimeter, with a strong predominance of polymorphonuclears. In 3 cases, infective viral particles were found in the fluid with anti-HIV antibodies. In 2 patients biopsy of the synovial membrane provided evidence of non-specific subacute synovitis. All X-ray films, including those of the sacro-iliac joint, were and remained normal. The course of the joint disease was acute and regressive in 5 cases, chronic and prolonged in the remaining 5 cases. In 5 patients the arthropathies were the first clinical manifestations of the HIV infection. Three patients who had stage IV C AIDS died; the others were in stages II (5), III (1) or IV E (1) and did not progress to a more severe stage. This study shows that various types of inflammatory arthritis may occur in HIV positive patients. In most cases the arthritis is reactive, but certain data suggest that it may be directly related to the virus in some patients.