Obtaining free resection margins is the main goal of oncological surgeons. Narrow-band imaging (NBI) has been recently used to help define resection margins in transoral laser microsurgery for laryngeal carcinoma. The aim of this study was to evaluate the effect of intraoperative NBI in defining the surgical resection margins of oral and oropharyngeal cancers. Between January 2014 and March 2015, NBI was used intraoperatively after an initial definition of resection margins with white light in 26 patients (group A). The rate of superficial positive margins at definitive histology was compared with that of a historical cohort of 44 patients (group B) previously managed without the use of intraoperative NBI. A statistically significant reduction in the rate of positive superficial margins was observed at definitive histology in group A (P = .028). NBI helped to identify the presence of dysplasia and cancer around the visible tumor not otherwise detectable with visual examination alone. NBI could be a useful tool for obtaining free resection margins in oral and oropharyngeal carcinoma.