Herpes zoster oticus usually accompanies vestibulopathy on the ipsilateral ear. However we have encountered two herpes zoster oticus patients with bilateral vestibulopathies. Bilateral vestibulopathy was detected on the 2nd month and 19th day of herpes zoster oticus, respectively. While the contralateral vestibulopathy was detected 2 month after the ipsilateral vestibulopathy in the first patient, the vestibular function deteriorated simultaneously on the 19th day in the second patient. It seems that the bilateral vestibulopathy was caused by an autoimmune process in both cases, but the initiating event is different. The ipsilateral vestibular damage may have sensitized the immune system in the first patient resulting in sympathetic vestibulopathy. But in the second patient, the ipsilateral cochlear damage may have sensitized the immune system resulting in simultaneous bilateral vestibulopathy.