On the basis of the degeneration behaviour two different types of cochlear afferent neurons can be distinguished. About 95% of all cochlear neurons are of the common type I with large myelinated spiral ganglion cells. They show complete retrograde degeneration after transsection of the cochlear nerve and they are exclusively connected to the inner hair cells. The remaining 5% neurons are of type II and do not degenerate after transsection of the cochlear nerve. Their smaller, unmyelinated ganglion cells are clearly distinguished from the type I ganglion cells. They provide the entire afferent nerve supply to the outer hair cells. The functional implications of such a divergent inner hair cell afferent innervation and a convergent outer hair cell afferent innervation are discussed.