Peliosis of the spleen was found in 10 out of 1,200 cases autopsied from 1977 through 1980 in our laboratory. Eight such cases had no peliosis of the liver. Histologically, it was noticed that the parafollicular areas were the most common sites of the lesions, and this feature seemed to be important for the histologic differentiation of peliosis from simple dilatation of splenic sinuses resulting from passive congestion. The clinical and anatomic features of these cases are described and previously reported cases of peliosis of the spleen are reviewed briefly.