Cochlear implantation is considered to be of significant value for postlingually deaf adults and children and also for prelingually deaf children.Adequate rehabilitation is important for postlingual deaf subjects, but is more crucial for prelingually deaf children to maximize the benefits of cochlear implantation.In this study, the current concepts of cochlear implantation and the results of subjects implanted at the cochlear implant unit, Cairo University were evaluated.The study group consisted of 18 adults and 24 children, data about subject selection, examinations, surgery and the outcome were discussed. The results of this study are in good agreement with those of other authors concerning audiometric gain and open set speech discrimination in adults, as well as audiometric gain and language development in children.