Sixty wild hippopotami killed at random on Lake Edward, Queen Elizabeth National Park, Uganda were autopsied. Schistosomal hepatitis and its complications, biliary coccidiosis, and fascioliasis were the most significant findings. These diseases may be of ecologic importance. A case of congenital bronchiectasis and one of bilateral pheochromocytoma were found. A tumor-like mass, possibly of viral origin, was found in a thyroid. Arteriosclerosis, a mild disease in hippopotami, with fibromuscular medial plaques, progresses throughout life. It produces no significant morbidity. Endocarditis, particularly in the right chambers, occurs frequently, apparently caused by schistosomiasis. Similarities to endemic endomyocardial fibrosis of man, particularly geographic distribution, site of lesion, and, to a lesser extent, structure of lesion, are discussed.