A 76-year-old man with spontaneous rupture of a hemangiosarcoma of the spleen, together with a review of 49 previously reported patients with splenic hemangiosarcoma are presented. Twenty-three were women and 27 were men. All but 3 were adults. Fiften were 50-59 years of age. The symptomatology was nonspecific. Three patients developed microangiopathic hemolytic anemia. Spontaneous rupture occurred in 17 cases (34%). Metastases occurred in 42 cases; they were primarily hematogenous and most often in the liver. Lymph node involvement, however, was present in 13 cases. The prognosis of untreated splenic hemangiosarcoma is poor. Three of 25 patients survived a year or more after the initial onset of symptoms. Splenectomy before rupture is advisable, since 5 of 19 patients survived at least 1-5 years. It is suggested that hemangiosarcoma be considered in patients with: 1) splenomegaly without evidence of malignant lymphoma or leukemia, 2) splenomegaly with microangiopathic hemolytic anemia, and 3) unexplained intraperitoneal hemorrhage.