Progressive genetic sensorineural hearing loss is a common problem in adults which is frequently incorrectly diagnosed or escapes diagnosis as to etiology altogether. If the hearing problem becomes manifest in the twilight of the patient's life it is often identified with the nondescriptive term “presbycusis.” In all patients with sensorineural hearing loss, extrinsic (environmental) causes should be ruled out after which intrinsic or genetic etiology should strongly be considered, recognizing that extrinsic factors can be superimposed. A group of young adults was studied and diagnosed as having genetic progressive hearing loss. Polytomography ruled out the theoretical possibility of cochlear otosclerosis. The diagnosis of this disorder rests most heavily on the history and audiometric configuration which is characteristically flat or basin shaped with fairly good discrimination. Of further diagnostic significance was the fact that some patients, early in the course of their difficulty, presented with a predominantly low- or high-frequency loss which, over time, assumed a flat audiometric shape. The most important pathological finding from human temporal bone studies was atrophy of the stria vascularis.