A 38-year-old man was admitted to our hospital with complaints of palpitation and shortness of breath. On auscultation, presence of severe aortic regurgitation was found. Seven years prior to admission, he had undergone rectal polypectomy complicated by postoperative serious hemorrhage which had led to the diagnosis of von Willebrand's disease. Aortic valve replacement with a Björk-Shiley prosthesis was performed under routine cardio-pulmonary bypass. He received Confact-F as a replacement therapy of factor VIII throughout the perioperative period. His operative and postoperative courses were uneventful without difficulties in hemostasis. The patient was placed on a regimen of anticoagulation (Warfarin sodium) without increase in the bleeding tendency. He is asymptomatic and doing well six months after the operation.