Vertebral aneurysms are not necessarily rare. In general neck clipping of vertebral aneurysms is the surest method for treatment of aneurysms, but as for vertebral aneurysms, it is often difficult to clip the neck without danger, because they cross over lower cranial nerves and are often fusiform. The indication of proximal ligation of the vertebral artery for treatment of vertebral aneurysms has not yet established. This procedure in 28 cases in the literature and our 3 cases treated successfully was discussed and following results were obtained. 1) Proximal ligation of the vertebral artery was useful for prevention of a rupture of vertebral aneurysms. 2) Intracranial ligation of the vertebral artery was better than the ligation in the cervical region. 3) It was necessary for the diameter of the contralateral vertebral artery to be, at least, approximately same. 4) In order the diameter of the vertebral artery to enlarge to 1.2 times as wide as that of a preoperative state, and the blood flow in the basilar artery to be enough, it was necessary for the contralateral vertebral artery not to be sclerotic.