목적: Many postlinguistically deaf adults have achieved improvement of speech perception through cochlear implantation. On the contrary, there are some adults who failed to achieve satisfactory performance of speech perception. In this study, we aimed to analyze the factors affecting low performance of speech perception in the postlinguistically deaf adults with cochlear implants 방법:Data from 115 adults who had cochlear implantation at Seoul National University Hospital from January 2000 to July 2013 were collected. Subjects were devided into two groups. One group consisted of 37 subjects who scored lower than 50 % in the K-CID sentence test 1.5 to 2.5 years after the implantation. The other group was composed of 75 subjects who scored higher than 70 %. We analyzed factors known for affecting performance after cochlear implantation, such as patients age at the implantation, duration of hearing loss, cause of hearing loss, and pure ton average threshold of the better ear. We also analyzed other factors such as gender, lefty-or-righty, tinnitus, duration of wearing hearing aid prior to the implantation, percentage of active electrodes, number of speech therapy sessions after the surgery, patients motivation and effort to perceive the speech, and support of family and friends. 결과:Univariable analysis revealed that the length of hearing loss, the percentage of active electrodes, patients motivation and effort and support of family were associated with the performance after cochlear implantation. Multivariable analysis revealed that the length of hearing loss, patients' motivation and effort and support from family were associated with the performance after cochlear implantation. 결론:Patients' motivation and effort to perceive speech and support from family are important factors for satisfying results after cochlear implantation. Based on these results, constant encouragement and speech stimuli from the medical staff also seems to be important.