A 59-year-old man was transferred to our hospital because of mural thrombus in the ascending aorta. He had suffered some neurological dysfunctions such as transient dysorientation. Electrocardiogram showed normal sinus rhythm without premature beats. Trans-thoracic echocardiogram and three-dimensional CT showed a mobile mural mass sticking to the ascending aortic wall. No coagulopathy was detected in the patient. The mural masses were thought to be a possible cause of the repeated cerebro-vascular symptoms. Under cardiopulmonary bypass and cardiac arrest, the masses were removed including the mass sticking to the aortic wall. Postoperative pathological findings showed the masses were organizing thrombi that had originated from the atherosclerotic aortic wall. Postoperative course was uneventful, and the patient was doing well one year after the operation without neurological dysfunction.