This study attempts to establish clinical criteria that would enable physicians to decide which patients with sudden cochlear and vestibular symptoms should be explored surgically in search of a perilymphatic fistula, in the absence of history indicating trauma to the inner ears. For this purpose, we studied forty-five patients whom we operated on because of suspected perilymphatic fistulas. The patients were divided into two groups: Group A (twenty patients) had previously undergone stapedectomy. Group B (twenty-five patients) had not undergone surgery in the past. Most of our patients experienced a rather acute onset of vertigo, unsteadiness, hearing loss, and tinnitus.We found no significant difference in the symptoms or signs between the patients who had a fistula and those in whom a fistula was not found, nor between those who underwent stapedectomy previously and those who did not. Most of the patients in Group B (75 percent) with fistula did, however, have a history of some stress or trauma preceding the sudden onset of symptoms. Yet some did not. We had three patients with no such history, nor had they undergone a previous stapedectomy. Basically, we are left with a dilemma: whether or not to explore a particular ear with appropriate symptoms and signs but without a traumatic history-knowing that about a quarter of these patients may have a perilymphatic fistula.