Loeys-Dietz syndrome is described as an aortic-aneurysm syndrome with widespread systemic involvement which is caused by heterozygous mutations in the genes encoding transforming growth factor ß receptors 1 and 2 ( TGFBR1 and TGFBR2, respectively). This disease is characterized by arterial tortuosity and aneurysms, hypertelorism, and bifid uvula or cleft palate and lack of ocular findings of Marfan syndrome and often present in childhood with significant cardiovascular problems. Marfan clinic in Samsung medical center is composed of many departments such as pediatrics, internal medicine, cardiovascular surgery, orthopedics, ophthalmology, radiology, laboratory medicine and genetics and coordinator and we describe 3 patients with Loeys-Dietz syndrome who was diagnosed by genetic test at various ages.