A 71-year-old male with disseminated intravascular coagulation (DIC) caused by abdominal aortic aneurysm was successfully treated surgically. He had aortic regurgitation, an old myocardial infarction, and nephrotic syndrome. The infrarenal part of the inferior vena cava, which was on the left side of the aneurysm, was temporarily transected during the surgical procedure. Preoperative heparin therapy was insufficient, but infusion of blood components during the operation and minimal dissection of the aneurysm were effective in controlling intraoperative hemorrhage. Hypofibrinogenemia and thrombocytopenia were normalized immediately after operation, and hemorrhagic diathesis was completely cured. In this case, the definitive treatment of DIC caused by an abdominal aortic aneurysm war removal of the lesion and the infusion of coagulation factors during the operation was effective in minimizing blood loss.