An aneurysm of the left sinus of Valsalva producing aortic valve regurgitation was treated by excising the aortic root including the aneurysm but leaving the aortic valve leaflets. The aortic valve was reimplanted inside a graft. Postoperative examinations revealed normal aortic valve function. In this case, the cause of aortic valve regurgitation was due to deformity of the aortic annulus. An aortic valve-sparing operation is an appropriate method for such a case.