We present a 55-year-old man with repeated transient symptoms of vertebrobasilar arterial pathology. Physical examination detected no signs that would indicate the stenosis of the proximal subclavian artery segment. Ultrasound detected hemodynamic disorder of right vertebral artery, which correspond to a partial subclavian steal syndrome. Angiography shows fusiform aneurysm of ipsilateral subclavian artery in which central part is the base of hypoplastic vertebral artery. In the literature are rare reports of cases of partial subclavian steal syndrome caused by aneurysmal expansion of subclavian artery.