This is a report of the management of a patient with chronic idiopathic thrombocytopenic purpura (ITP) and ischemic heart disease. High-dose transvenous gamma-globulin therapy (400 mg/kg/day for five days) was started five days prior to operation, yielding an increase in platelet count from 5.8 X 10(4)/mm3 to 12.8 X 10(4)/mm3. Platelet transfusion was used at the end of cardiopulmonary bypass and on the first postoperative day. There were no problems with hemostasis during the operative procedure and the postoperative course was uneventful. We prefer high-dose transvenous gamma-globulin therapy for ITP prior to open heart surgery as a treatment of choice.