Numerous neuropathologic sequelae of cardiopulmonary bypass have been reported. These include embolism, cerebral infarction, neuronal degeneration, subarachnoid hemorrhage and intracranial hemorrhage. These sequelae may account for the neurologic and behavioral desorders in the postoperative period. We report a case of intracranial hematoma following total correction of TOF. An emergency craniotomy was performed to evacuate the hematoma, but the patient failed to regain consciousness following surgery and expired on the 17th postoperative day. In this patient, two factors responsible for the pathogensis of intracranial hemorrhage anre postrulated. First, in the pressence of intraoperative heparin administration, significant hematoma formation may result from damage to the bridging during vein from minor head trauma or alterations in cerebral volume from fluid shift, which may occur during bypass. Second, preexisting arterivenous malformation may be a source of hemorrhage under heparin administration. These hematoma are potentially reversible, so early diagnosis and therapy is extremely improtant.