A patient with an aneurysm of the ascending aorta and calcific stenosis of a congenital bicuspid aortic valve, whose brother also had a stenotic congenital bicuspid aortic valve, is described. Predominant aortic stenosis at cardiac catheterization and the presence of an aneurysm distal to and not including the aortic valvular ring made the initial diagnosis of Marfan's syndrome unlikely. Cystic medial necrosis present in the aneurysmal wall probably arose as a consequence of poststenotic dilation. Adequate noninvasive evaluation of the ascending aorta requires echocardiographic studies, as well as a chest x-ray film.