Evidence for binaural plasticity resulting from late-onset deprivation comes from behavioral adaptation in humans following experience of abnormal binaural cues, from physiologic changes in the organization of the cerebral cortex, and from anatomic rewiring of some of the pathways underlying binaural hearing in the brain stem. Some of this evidence is indirect, and the long-term functional consequences of these changes in the nervous system are unclear. Nevertheless, there are now sufficient data available on plasticity in mature nervous systems to warrant a substantially increased research effort in this field. Among the questions to be addressed are the site(s) of reorganization in the auditory system, the effects of different types of deprivation, and the neural mechanisms underlying the plasticity.