Objective To investigate the relationship between mismatch negativity（MMN） and speech discrimination scores in a group of postlingually deaf adults after cochlear implantation. Methods 10 CI adults with postlingual profound hearing loss were enrolled in this study. The MMN and open set monosyllabic speech discrimination rate were tested at the 1 st month

the 3 rd month and the 6 th month after the cochlear implant was switched on. Results MMNs was evoked in 5 of 10 cases at the 1 st month

the 3 rd month and the 6 th month after CI device was switched on; In the other 5 cases

the MMN were difficult to distinguish at the three time points

but the group averaged MMN waveforms at the 6 th month were identified. The speech recognition rate of 1 month after switch on was significantly different from that of both 3 months and 6 months. Among the 10 subjects

MMN amplitude increased and latency decreased with the speech discrimination score rising. The MMN amplitude and latency showed no statisticall significance between the three groups. Conclusion MMN amplitude is consistent with speech discrimination scores in CI adults at 1-6 months after CI was switched on.