Marfan syndrome is an infrequent genetic disorder of connective tissue whose clinical manifestations mainly affect the cardiovascular, ocular and musculoskeletal systems. Serious cardiovascular manifestations are generally the cause of mortality of Marfan patients. Thromboembolic venous disease is intimately related to different risk factors: inherited, acquired, mixed or unknown; hyperhomocysteinemia is a moderate risk factor for venous thromboembolism. We present the case of a 47-year-old woman with Marfan syndrome associated to a painless type A aortic dissection, who simultaneously suffered venous thromboembolism of left upper and lower limbs with pulmonary embolism. Hyperhomocysteinemia was found through thrombofilia screening. The patient's condition has evolved favorably.