In more than 80% of cases of hearing loss, the cause is directly or indirectly related to the degeneration and death of sensory hair cells and their associated spiral ganglion neurons (M. C. Holley, 2002; J. F. Willot, 1991). Although certain animal species have the ability to regenerate lost hair cells, humans do not. If regeneration of these hair cells or the generation of new hair cells became possible, then many individuals would be given the potential to restore hearing. Several laboratories around the world are currently attempting to understand the molecular factors and mechanisms necessary for cochlear hair cell function, death, and (re)generation in the animal and human species. Three leading approaches-gene therapy, cell transplant, and drug delivery-are making rapid advances in generating new or restored hair cells in the human cochlea. This article includes a description of cochlear hair cell functioning, the history of hair cell regeneration efforts, and a comparison of approaches to cochlear hair cell regeneration.