Perilymph fistulas may manifest themselves either by otologic symptoms, as in cases of small fistulas, or primarily through neurologic symptoms, as with large fistulas. A case history is presented of a 3-year-old girl with recurrent bouts of meningitis who was found to have a large perilymph fistula. She had a right undeveloped cochlea and labyrinth, as well as multiple defects of the medial wall of her middle ear. The only way of preventing the recurrent bouts of bacterial meningitis in cases of large perilymph fistulas is surgical repair. Our conclusion is that, considering the problems involved in cases of large congenital perilymph fistulas, a simple closure of the fistula is not sufficient and the method of choice is obliteration of a deeper structure--such as the vestibule itself.