This was a retrospective study to assess the utility of narrow band imaging (NBI) in the detection of a primary site in carcinoma of unknown primary (CUP). Patients with CUP who underwent transoral robotic surgery (TORS) and preoperative imaging with NBI and white-light imaging (WLI) from 2016 to March 2019 at Emory University Hospital Midtown, Atlanta, Georgia, were identified. CUP was defined as a p16 positive squamous cell carcinoma cervical level II/III lymph node without a localised primary tumour following clinical and radiological examination, as well as examination under anaesthesia. NBI and WLIs obtained in clinic with flexible endoscopy were reviewed just before surgery to identify a potential primary site (areas of heterogenous/inconsistent blood flow or area of stippling on NBI). The histology from surgical resection through the centre’s TORS unknown primary protocol (ipsilateral tonsillectomy to p16 positive node followed by frozen-section analysis and, if negative, ipsilateral lingual tonsillectomy and, if frozen analysis negative, then contralateral lingual tonsillectomy) was then compared with the suspected primary on NBI. A total of 29 patients presented with CUP. Nine had preoperative NBI, of which eight (89%) indicated a potential primary site (four tongue base and four tonsil). In all of these eight cases, the site of primary corresponded to the primary identified on TORS resection histology. In the one case where NBI did not identify a primary, TORS surgery also failed to identify one. In patients not imaged with NBI, 15 of 20 (75%) primary sites were identified. In four of 23 (17%) cases where a primary site was identified with the TORS protocol, excision was incomplete. These four cases were not imaged with NBI preoperatively. Although the sample size is small precluding any statistical significance, this study highlights the potential of using NBI to aid identification of primary sites in CUP and aid complete resection of tumours. Further prospective studies using NBI in the operating theatre will be useful in assessing NBI’s usefulness in this area and to see if this translates into increased survival and decreased treatment-related morbidity.