The mouse is the model organism for the study of hearing loss in mammals. In recent years, the identification of five different mutated genes in the mouse (Pax3, Mitf; Myo7a, Pou4f3, and Myo15) has led directly to the identification of mutations in families with either congenital sensorineural deafness or progressive sensorineural hearing loss. Each of these cases is reviewed here. In addition to providing a powerful gateway to the identification of human hearing loss genes, the study of mouse deafness mutants can lead to the discovery of critical components of the auditory system. Given the availability of several mouse mutants that affect possible homologues of other human deafness genes, it is likely that the mouse will play a key role in identifying other human hearing loss genes in the years to come.