A case is reported of downbeat nystagmus associated with compression of the root of vestibulocochlear nerve by vertebral arteries, which was revealed by magnetic resonance imaging. Chief complain of the patient was positional vertigo, which aggrevated at left decubitus position. Downbeat nystagmus was increased in left Dix-hall pike test. Tetsuo et al, reported downbeat nystagmus with compression of dolichoectatic vertebral arteries to the medulla oblongata and surgical neurovascular decompression of the dolichoectasia reverses the progression of symptoms if permanent neurologic damage has not already occurred. Key Words : Vertical nystagmus, Vertebrobasilar dolichoectasia, Vestibulocochlear nerve