Tuberculosis is currently one the more frequent opportunistic infections in patients infected by Human Immunodeficiency Virus (HIV) in our setting. Its extrapulmonary localization is considered as diagnostic of the Acquired Immunodeficiency Syndrome (AIDS). We have evaluated the epidemiological, clinical, microbiological, histological and immunological characteristics of 120 patients in the Asturias region who had a tuberculosis diagnosed in any localization, during the period between 1984 and 1991, belonging to a series of 570 patients infected by HIV. Pulmonary types were comparatively analyzed to the extrapulmonary and disseminated ones. Tuberculosis was pulmonary only in 44 occasions (PT), in 36 it was extrapulmonary (EPT) and in 52 disseminated (DT). The more frequent risk factor for the HIV infection was the parenteral consumption of drugs (78.8%). The final diagnosis was microbiologic in 81% of the cases, while bacilloscopia was positive in 62% of the cases. The histologic study showed the presence of granulomas in 86% of the tissues studied and necrosis in 81%. EPT and DT were related with a worse immune situation, bigger mortality rates attributed to tuberculosis and worse survival (p 0.069). Tuberculosis in patients infected by HIV appears mainly in CDVP, being its symptoms the normal ones; but extrapulmonary forms are clearly predominant and within this group those with a ganglionar localization. Normal diagnostic procedures yield a good result. EPT and DT are significantly related to a more severe immunodeficiency in comparison with PT. Survival and prognosis are better in the PT group.