Background <p>The adenoma detection rate is a key colonoscopy quality indicator, but the adenoma miss rate (AMR) is more strongly linked to post-colonoscopy colorectal cancer risk. While studies examined high-definition colonoscopy and AMR, no studies have assessed its impact on consecutive polypectomy.</p> Aim <p>This study aimed to identify adenomas missed in screening or surveillance colonoscopy and determine if the endoscopic system affects the miss rate.</p> Methods <p>This retrospective study analyzed patients referred to Dong-A University Hospital for polypectomy after polyps were detected during screening or surveillance colonoscopy at 24 healthcare institutions. Endoscopic systems used in these colonoscopies were classified as FHD (FHD) or non-FHD. Consecutive polypectomies were performed by a single expert between March 2020 and February 2022 using the FHD system. The AMR was compared and analyzed for screening or surveillance colonoscopies performed using FHD endoscopic systems and those using non-FHD endoscopic systems.</p> Results <p>Of 542 polyps, 186 were missed (miss rate: 25.22%). Miss rates for adenoma and advanced neoplasia were 27.34% and 14.69%. Univariate analysis identified age, adenoma count, and endoscopic system as significant factors. However, only the endoscopic system remained significant in the multivariate analysis. In screening or surveillance colonoscopy, the use of FHD endoscopic systems demonstrated a lower AMR compared to non-FHD systems (21.86% vs. 31.41%, <i>P</i> = 0.014).</p> Conclusion <p>The use of FHD endoscopic systems reduced AMR compared to non-FHD systems.</p>