We experienced a case of open heart surgery for correction of ventricular septal defect and patent ductus arteriosus in five years old boy with hemophilia A. Factor VIII activity in this patient was 0.7% of normal activity. He received 2,000 unit of factor VIII intravenously for loading dose and has been infused 6 unit/kg/hour for 12 hours before the operation. And his factor VIII activity was 68% in the morning of the operation day. During the operation, he received 6 unit/kg/hour of factor VIII. After intracardiac anomaly was repaired and protamine was injected, we administrated 1000 unit of factor VIII. At that time, his factor VIII was 57%. After operation was done, he received 6 unit/kg/hour of factor VIII during stay in ICU and postoperative 14 days. His factor VIII activity was maintained at 36~104% during stay in hospital. So we report a successful case of perioperative management for the open heart surgery in patient with hemophilia A.