A 65-year-old man with an isolated aneurysm of the proximal right subclavian artery (SCA) (diameter, 50 mm) was successfully treated with a deliberate surgical strategy described here. Because of the occluded left vertebral artery (VA) and poor development of the circle of Willis, the distal portion of the right SCA was bypassed from the ascending aorta before resecting the aneurysm in order to maintain blood flow to the brain through the right VA. Consequently, the patient recovered without neurological complications. We conclude that conventional surgery remains effective for complex vascular diseases even in the era of advanced endovascular surgeries.