SummaryThe authors report 4 cases of Marfan’s syndrome with cardiovascular lesions : aortic insufficiency and aneurysm of the ascending aorta (1 case), mitral insufficiency and dilatation of the sinus of Valsalva (1 case), aortic insufficiency (2 cases). The patient presenting aortic insufficiency and aneurysm of the ascending aorta was successfully operated upon. The pathogenesis of the aortic and mitral lesions is discussed. In one patient association with cystinuria and in another with polycystic kidneys was found.