Loeys-Dietz syndrome (LDS) is characterized by vascular findings (aortic aneurysms and dissections) and skeletal manifestations. Since aortic dissection occurs at smaller aortic diameters than observed in Marfan syndrome, early and aggressive surgery is recommended for patients with LDS. A 45-year-old man who underwent aortic valve replacement for aortic regurgitation at the age of 33 was transferred to our hospital with the diagnosis of acute aortic dissection. We performed emergeny ascending aortic replacement, and suspected LDS because of his specific physical characteristics after surgery. His postoperative course was uneventful, however, computed tomography (CT) performed at 2 weeks after operation showed the new entry at the distal anastomotic site, patent false lumen of the descending aorta and rapid enlargement of the distal aortic arch. Therefore, we performed total arch replacement with the elephant trunk method at 3 weeks after the emergency operation. Mutation of the TGFBR2 gene was found and we finally diagnosed LDS. One year after, complete thrombosis of the false lumen of the descending aorta and decrease in size of the distal aortic arch was observed by CT.