Sudden hearing loss in the contralateral ear is a rare but catastrophic complication of acoustic tumor surgery. The seventh case in the literature is reported. Hearing can return, but this is less likely when the tumor was large or a suboccipital approach was used. A short course of corticosteroids, carbogen, and histamine cannot be shown to be effective but is probably worthy of consideration. Cochlear implantation may have a role if irreversible hearing loss persists 18 months after surgery.