Strict antihypertensive therapy for thoracic aortic aneurysm is extremely important. Administration of beta-blocker or angiotensin II receptor blocker (ARB) has been reported to prevent aneurysm enlargement in patients with Marfan's syndrome. While there is no significant association between hypertension and the risk of development of abdominal aortic aneurysm, a large-scale case controlled study showed a lower frequency of ruptured aneurysm in patients treated with ACE inhibitors. The beneficial effects of ACE inhibitor and/or ARB treatment should be confirmed by large-scale randomized controlled-trials. In patients with peripheral arterial disease, administration of beta-blockers has been considered to exacerbate lower limb ischemic symptoms; however they have recently been shown to be used safely in patients exhibiting intermittent claudication.