Vascular complications of Behçet's disease particularly affect the venous system. Arterial lesions include thrombosis and aneurysms. There are few reports of aortic involvement, usually of the abdominal aorta. Aortic arch involvement has not been reported previously. A patient with Behçet's disease who developed an aortic aneurysm involving the ascending aorta to the hiatus with massive incompetence of the aortic valve is described.