Human immunodeficiency virus (HIV)-infected multinucleated giant cells previously were detected only in the central nervous system of HIV-positive patients. Reported here are the first cases in which such infected cells were observed outside the central nervous system, in the oropharyngeal lymphoid tissues. Tonsils and adenoids were removed individually from two asymptomatic homosexual men. Follicular hyperplasia and many interfollicular multinucleated giant cells most often in contact with or in close proximity of the mucous membrane were seen. The latter were positive for lysozyme, alpha-1 anti-chymotrypsin, OKM1, and S-100 protein in accordance with a histiocytic origin. In situ hybridization with an HIV envelope-specific RNA probe demonstrated the presence of viral RNA in these multinucleated giant cells. These findings support the role of peripheral histiocytes as a primary virus reservoir early in the disease. They also underline the potential role of oropharyngeal tissue as a primary target in some cases.