목적: It is well established that cochlear implantation provides significant benefit for prelingually profound deaf children. However, there are few studies that examined the long-term outcome of cochlear implantation beyond 10 years in prelingual deaf children. The purpose of this study was to examine the long- term benefit of cochlear implantation in children over 10 year experience with cochlear implantation with regard to auditory performance, speech perception, and academic status and determine the age effect at cochlear implantation on auditory performance for prelingually deaf children. 방법:The longitudinal development of auditory performance, and speech perception of 119 deaf children were analyzed after cochlear implantation and the academic status of the patients was recorded. Among the 119 children, 58 were feasible to analyze in this study. All children received a cochlear implant at 3.5 years 36 months (mean age SD). Implant experience ranged from 10 to 13 years of use. 결과:The children who received cochlear implant at younger age showed significant better auditory performance than children at older age of cochlear implantation. There was a significant effect of age at implantation on auditory performance by 10 years of age. The children continued to demonstrate improvements of auditory performance through 10 years of implant use after cochlear implantation. Among the patients, 44 children were in mainstream school and 14 children were in schools for the deaf. 결론:The present result indicates that speech perception and performance continue to improve over time for children at 5 to 10 years of cochlear implant use and earlier cochlear implantation showed to yield better auditory performance. The age at implantation is one of the important factors influencing on long- term outcome of cochlear implantation.