A male child, aged 3 years, with profound bilateral auditory disabilities participated in the present study. Through this study, the auditory perception and oral language of the deaf child were assessed before and after cochlear implantation. The procedures used in the evaluation of the child were the Scale of Auditory Integration for Young Children IT-MAIS, the Oral Language Assessment Questionnaire - MUSS, Functional Gain, hearing categories, language categories, and LING sounds. All procedures are part of the evaluation protocol of hearing-impaired children at the CPA Audiological Research Center, University of São Paulo Bauru campus. The tests were applied before and after cochlear implantation in the first year of use with quarterly reviews. The results obtained before the cochlear implant, when the child was using a conventional hearing aid, showed utilization of only 7.5% of their capacity and a linguistic performance of 5%. After 1 year of effective use of the cochlear implant, the child reached 100% hearing capacity and 97.5% oral linguistic performance. When comparing the performance of the child before and after cochlear implantation, a significant improvement in hearing thresholds was observed, which normalized along with age-appropriate language structuring. The findings of this study are consistent with the literature and point to the benefits that cochlear implants can bring to a child with profound bilateral hearing loss, who has no improvement using a conventional prosthesis.