Tissue slides obtained at autopsy from 80 cases with AIDS were studied immunhistochemically for infection with Toxoplasma gondii. In 35 cases (43.75%) toxoplasmosis could be found: in 22 cases (27.5%) only cerebral, in 9 cases (11.25%) cerebral and extracerebral and in 4 cases (5%) only extracerebral. Necrotizing lesions, due to the parasite could be seen in brain, heart, lungs, pancreas, adrenal glands and testis, only intracellular trophozoites without tissue damage in GIT, liver, lymphnodes, spleen, prostate, kidney and gl. parotis. The trophozoites and pseudocysts could be clearly demonstrated by immunohistochemistry.