Cochlear implantation in the paediatric population is now an accepted method of rehabilitating profoundly or totally deaf children. The problems of cochlear implantation in children with other significant medical problems are examined. A retrospective review of the records of the first 45 children implanted at our centre was carried out. The review focused on surgical factors and outcome in addition to variations in technique which have occurred since the programme began. Congenital hearing loss was the most common indication for implantation. Fifteen children (33 per cent) had other medical problems. Three cases of flap breakdown (two occurring after direct trauma to the package bed) and one case of a misplaced electrode requiring re-implantation accounted for the only major complications to date. Minor complications included hypertrophic scar formation and post-operative wound infection. All children were using their implants at the time of this review, but two have subsequently been explanted. Cochlear implantation of children with multiple medical problems requires acceptance of a slightly higher risk of complications.