The study covered 130 splenectomies performed at the University Hospital in Birmingham [USA] for hematologic disorders during a 12 yr period. There were 7 deaths of which 4 were related to sepsis in patients with malignant growths which probably impaired immune competence. Splenectomy was uniformly satisfactory for hereditary hemolytic anemia, for hypersplenism complicating rheumatoid arthritis and for the rare instance of primary hypersplenism. Splenectomy was usually salutary in idiopathic thrombocytopenic purpura and in autoimmune hemolytic anemia. When done for diagnosis, splenectomy was definitive in about 50% of the instances. Individual patients with thrombotic thrombocytopenic purpura, hairy cell leukemia and hypereosinophilia syndrome benefited. Splenectomy for hypoplastic or aplastic anemia in an attempt to increase percentage of platelets in actual circulation offered only questionable benefit and is rarely necessary for hypersplenism secondary to portal hypertension.