OBJECTIVES: To assess device failures as well as early postoperative, late postoperative, and medical complications occurring after cochlear implantation and to discuss their causes and treatments. Study DESIGN: Retrospective study of 500 consecutive cochlear implantations. SETTING: Tertiary referral center. PATIENTS: All patients receiving cochlear implants at our institution between 1989 and 2006. MAIN OUTCOME MEASURES: All complications and treatments were systematically reviewed with a maximum follow-up of 18 years. The number of reimplantations was calculated according to follow-up duration to determine the cochlear implant survival rate. Specific risks of reimplantation were calculated for groups with differing durations of implantation. RESULTS: The overall rate of complications was 16.0% (79 of 500), with minor complications accounting for 5.6%; major complications, 3.2%; and reimplantations, 7.2%. Reasons for revision surgery were device failure, infection, trauma, and "soft device failure" (failure despite normal results from integrity testing). Revision surgery was performed in 51 of the 500 cases (10.2%), and other complications were managed medically (28 of 500; 5.6%). The rate of hard and soft device failures was 6% (30 of 500). Seventy-two percent of reimplantations occurred within 5 years. The risk of severe infection (eventually requiring explantation) was 1.4% (7 of 500). There was 1 case of transient facial palsy following surgery (0.2%), and the incidence of postsurgical meningitis was 0. CONCLUSIONS: Cochlear implantation is a safe technique with a relatively low complication rate; however, certain complications may require specific attention to prevent or correct them.