Perilymph fistula is caused by an abnormal communication between the perilymph space and the middle ear. The etiology is either congenital or acquired. The congenital fistula can be associated or not with clinical symptoms or radiologically detectable abnormalities of the temporal bone. In patients presenting congenital fistula without symptoms or radiologically detectable abnormalities, little malformations of the middle ear may be detected during surgery. The acquired fistula can be caused by iatrogenic trauma, physical injury or erosion. As far as therapy is concerned, surgical treatment can be performed and the perilymph fistula thus represents one of the few causes of sensorineural hearing loss that can be treated surgically. However, the main challenge is the identification of those patients that need to undergo an exploratory tympanotomy, since there are no clinical-audiologic symptoms or radiographic indicators that can be considered pathognomonic of perilymph fistula. The aim of this review of the literature is to define the guidelines for preoperative diagnosis to indicate exploratory tympanotomy both in children and in adults. On the basis of our results, exploratory tympanotomy should be performed in patients with vertigo and/or progressive, sudden or fluctuating hearing loss in association with one or more than one of the following elements: a history of cranial trauma, radiographically detectable abnormalities of the inner ear, congenital malformations of the head, recurring meningitis, positive fistula test. The surgical treatment consists in placing a graft of temporalis fascia or tragal perichondrium and it usually results in a significant improvement of vestibular symptoms and sometimes of the hearing function as well.