We reported six patients with Marfan's syndrome, studied retrospectively from May 1990 to April 1992 in the department of Cardiology in Dakar. Morphological, cardiovascular, skeletal and ocular abnormalities have been reviewed. All the patients had been evaluated by echocardiography. Prevalence of Marfan's syndrome among congenital heart diseases during this period was 4.8%. The mean age was 27.6 years. The mean height was 1.80 m (range 1.38-2.02 m) for a mean weight of 62.8 kg. All the patients had dolichostenomely and arachnodactyly. Kyphosis or scoliosis was present in 5 cases. Chest deformities (pectus carinatum and excavatum) were present in 5 cases. 5 patients had hyperextensible joints. 5 patients had ocular abnormalities. Cardiac pathology was found in 5: mitral prolapse with insufficiency in 2; mitral prolapse with aortic dystrophy in 2; and isolated dilatation of ascending aorta in an other. One patient with diffuse Marfan's syndrome died of cardiac failure. Our study confirm polymorphic manifestations of Marfan's syndrome and the frequency of cardiac abnormalities which are the major determinants of life-prognosis in these patients. Echocardiography is very useful as a noninvasive method for defining the extent of cardiovascular involvement and following its course, for more appropriate treatment.