Studied were histopathologically the viscera (liver, lung, kidneys, heart lymph nodes, and brain) of 15 animals (10 ewes and 5 lambs), experimentally infected with blood taken from sheep donors having acute babesiasis. During the experimental period 9 of the animals died, and 6 were killed within the interval from the 4th to the 9th day. Dystrophic changes were observed in the epithelial cells of the liver and the kidney tubuli as well as pycnosis of the gangliar cells. In some of the tubuli there were hyalin cylindroids. The heart presented an edema of the endocardium with leucocyte infiltration. In the lymph nodes there were hyperemia with hemorrhages and edema with leucocyte infiltration of sinuses and follicles. It was established that in sheep babesiosis the characteristic morphologic changes appear on the fourth day. The dystrophic foci in the liver, the activation of the endothelium, the finding of hemosiderin in the Kupffer cells as well the diffuse leucocyte infiltration associated with the presence of parasites in the erythrocytes may well be referred to as histomorphologic signs in the postmortal diagnosis of babesiasis.