목적: Hearing in Noise Test (HINT) is designed to measure the speech perception performance in quiet and noisy environment. The purpose of this study was to evaluate speech perception according to duration of implant use and noise direction and to identify factors contributing to speech perception in noise. 방법:Thirty-two CI users were tested with K-HINT. All participants were tested at pre-implantation and 3 months, 6 months and 1 year after application of CI to compare reception threshold score (RTS) according to the duration of implant use. To identify the factors contributing to speech perception in noise, we analyzed the correlation of RTS with the patient age, age of implantation, duration of implant use, and period of hearing loss. 결과:In prior to cochlear implantation, the results of RTS were undetermined in all thirty-two patients. Also, there was no significant difference of RTS according to the duration of implant use. However, there was an improvement of 2.3dB in the SNR between 3 months and 1 year after application of CI where at least 9.6dB was necessary for the speech recognition in noise after 1 year. When noise was presented in the ipsilateral side of the CI device, SNR was significantly higher than when noise was presented in the front or contralateral side to the device (p<0.05). In consideration to factors contributing to HINT performance, only the period of hearing loss significantly correlated with SNR in noise conditions (p<0.05). 결론:According to our results, at least one year of cochlear implant use is required to enhance the speech perception ability in noisy conditions. Furthermore, the period of hearing loss is the only factor affecting the speech perception ability of CI users in noisy environment.