Previous studies had attempted to identify factor(s) that can predict the audiologic preformance with conchlear implant device. However, no single factor showed a strong correlation with the audiologic performance. Nineteen adult cochlear implantees who received a rehabilitation for 3 months or more were selected for this study. Each five preoperative(age at onset of hearing loss, duration of deafness, development of language, level, dynamic range, number of usable electrodes, period of device use) factors were chosen. We conducted a statistical analysis(simple correlation and multiple regression) to determine which factor(s) contribute(s) to the phoneme recognition ability. The important factors to affect the audiologic performance preoperatively were duration of hearing loss and levels of language development. Postoperatively, the duration of device use and dynamic range were remarkably contributed to the phoneme recognizability. Overall, the duration of hearing loss and period of device use showed a strong correlation with the audiologic performance.