ABSTRACT Purpose Cross-cultural adaptation and translation of the Nijmegen Cochlear Implant Questionnaire (NCIQ) into Brazilian Portuguese and analysis of quality of life (QoL) results in adults with cochlear implant (CI). Methods The NCIQ instrument was translated into Brazilian Portuguese and culturally adapted. After that, a cross-sectional and clinical QoL evaluation was conducted with a group of 24 adults with CI. Results The questionnaire title in Brazilian Portuguese is ‘Questionário Nijmegen de Implantes Cocleares’ (NCIQ-P). The version of the NCIQ questionnaire translated into Brazilian Portuguese presented good internal consistency (0.78). The social and physical domains presented the highest scores, with the basic and advanced sound perception subdomains achieving the highest scores. No correlation between gender and time of device use was found for the questionnaire domains and subdomains. Conclusion The cross-cultural adaptation and translation of the NCIQ into Brazilian Portuguese suggests that this instrument is reliable and useful for clinical and research purposes in Brazilian adults with CI.