OBJECTIVE Hypernasality is considered a prevalent speech abnormality that could significantly contribute to the unintelligibility of the hearing-impaired speakers. The aim of this study was to evaluate the effect of cochlear implantation and the duration of hearing loss on nasalance of speech of a postlingually impaired group of Saudi adult patients. METHODS Retrospective study. METHODS This study included 25 postlingually hearing-impaired patients who underwent cochlear implantation and 25 age-matched control subjects. Patients were divided into three groups according to the duration of hearing loss. The nasometric data of the hearing-impaired group were compared with the control group. Also, the preoperative values were compared with the postoperative values 6, 12, and 24 months after surgery. RESULTS Significant differences were demonstrated between the preimplantation nasalance scores of the three subgroups and between the patients and control groups. There were statistically significant differences demonstrated between the pre- and the postimplantation nasalance values for the three groups of patients. CONCLUSIONS Cochlear implantation appears to have significant effects on improving the nasalance of the speech of postlingually hearing-impaired adult patients. However, the degree of improvement might vary according to the duration of hearing loss the patients had preimplantation.