A syndrome termed perilymphatic hypertension is described as being seen in a small subset of patients with sudden sensorineural hearing loss. A patent or semipatent cochlear aqueduct or modiolus are considered precursors to this condition. Perilymphatic hypertension is believed to predispose to perilymphatic fistula, which may be part of the process of resolution. The pathogenesis for perilymphatic hypertension and fistula are hypothesized and discussed. Treatment for this subset of patients consisted of paracentesis of the round window membrane followed by grafting, with improvement of hearing in certain patients. In no instance did hearing subsequently decrease.