In childhood, inadequately rehabilitated hearing loss leads to impaired language acquisition and social, mental and emotional development. In adults, social withdrawal due to limited communication skills is often a consequence of unsatisfactory hearing rehabilitation. Therefore, in patients with profound hearing loss, the indication for cochlear implantation should be considered. Technical advances in cochlear implant development, as well as in microsurgical techniques and the rehabilitation process, have led to an expansion of indications in recent years. Adequate hearing rehabilitation is associated not only with an improvement in hearing function and speech understanding, but also with an increase in quality of life at all ages. In patients with unilateral profound hearing loss, cochlear implantation leads to an improvement of speech understanding and localization ability as well as to a reduction of the head shadow effect and tinnitus. The indication process, surgical treatment and the subsequent rehabilitation process require interprofessional cooperation in specialized centers.