Marfan Syndrome is an autosomal dominant connective tissue disorder due to mutations in the fibrillin-1 gene. The diagnosis is based on the identification of major and minor diagnostic criteria in the skeletal, ocular, cardiovascular, and central nervous organ systems. The primary cardiovascular manifestation is progressive dilation of the aortic root, eventually leading to aortic dissection or rupture. Echocardiography is used to visualize the aortic root and proximal ascending aorta. Measurements are usually taken on the aortic valve annulus, maximal diameter at the sinuses of Valsalva, sinotubular junction and the more distal aorta. Aortic dilation in Marfan Syndrome commonly occurs at the sinuses of the Valsalva and is defined as aortic root diameter above the upper limit of the 95% confidence interval of the distribution in a large reference population. Sometimes the dilation can be asymmetric so it is important to have measurements in the transverse plane of the aorta. Secondary echocardiographic findings include tricuspid and mitral valve prolapse as well as dilation of the main pulmonary artery.