Over a period of 20 years, splenectomy has been performed upon 216 patients with idiopathic thrombocytopenic purpura. Splenectomy resulted in an immediate and sustained platelet response in 72 per cent of these patients. An additional 7.4 per cent of the patients had a sustained platelet count of 150,000 per cubic millimeter develop while off all drug therapy within the first postoperative year. Of the remaining patients who failed to meet these criteria, only one died of subsequent thrombocytopenic bleeding and only eight remained on any therapy with steroids or other immunosuppressive agents at last follow-up examination.