The absence of hearing, as in congenital deafness, affects normal development of the auditory brain resulting in deficits in spoken language. Cochlear implants provide direct stimulation to the central auditory nervous system of hearing impaired children allowing cortical development to progress. However, implantation needs to take place within a brief window in early childhood for it to be maximally effective to allow children to acquire speech and oral language. In this review, we describe age cut-offs for a sensitive period for central auditory development in children who receive cochlear implants. We review consequences for cortical re-organization and cortical de-coupling when children receive cochlear implants after the end of the sensitive period.