OBJECTIVE This study aimed to evaluate the reasons for cochlear implant (CI) revision surgeries in pediatric and adult groups. METHODS A total of 490 CIs were used for 423 patients between August 2005 and August 2019. Among these, patients who underwent a CI revision surgery were identified retrospectively. The reasons for CI revision surgeries were classified mainly as medical problems and device failure. These were also determined according to implant brands. RESULTS Of 423 patients with a CI surgery, 27 (6.3%) underwent a CI revision surgery. The revision implant rate was 4.9% for the pediatric group and 1.4% for the adult group. Five patients underwent a CI revision surgery due to medical problems (23.8%) and 16 due to device failure (76.2%) in the pediatric group, while 3 patients (50.0%) underwent a CI revision surgery due to medical problems and 3 (50.0%) due to device failure in adults. CONCLUSIONS A CI surgery is safe for patients with severe-to-profound sensorineural hearing loss, although a CI revision surgery has some potential. Device failure is the most common cause in children. It may be due to early implantation, frequent fall when children learn walking, or impaired vestibular function.