The Marfans syndrome is a generalized connective tissue disease involving eye, musculoskeletal system, cardiovascular system, and inherited autosomal dominant with various expression type. The cardiovascular complications such as aortic aneurysm, aortic dissection, aortic regurgitation, mitral regurgitation and aortic dissection which usually occurs in previously normal sized aorta are poor prognostic factors. However, the aortic dissection which developed in patient with Marfan syndrome and aortic aneurysm was rare. We experienced one case of dissecting aneurysm in patient diagnosed as previous aoritc aneurysm, aortic regurgitation, and Marfan syndrome, receiving successful operation.