BackgroundComplete mesocolic excision (CME) or D3 lymphadenectomy led to survival benefits for locally advanced right colon cancer, but with vague definitions in anatomy and debated surgical hazard in clinic. Aiming to achieve a precise definition of it in anatomy, we proposed laparoscopic right hemicolectomy (D3 + CME) as a novel procedure for colon cancer. However, the surgical and oncological results of this procedure in clinic were uncertain.MethodsWe performed a cohort study involving prospective data collected from a single-center in China. Data from all patients who underwent right hemicolectomy between January 2014 and December 2018 were included. We compared the surgical and oncological outcomes between D3 + CME and conventional CME.ResultsAfter implementation of exclusion criteria, a total of 442 patients were included. D3 + CME group performed better in lymph nodes harvested (25.0 [17.0, 33.8] vs. 18.0 [14.0, 25.0],P< 0.001) and the proportion of intraoperative blood loss ≥ 50 mL (31.7% vs. 51.8%,P< 0.001); no significant difference was observed in the complication rates between two groups. Kaplan–Meier analysis demonstrated that a better cumulative 5-year disease-free survival (91.3% vs. 82.2%,P= 0.026) and a better cumulative 5-year overall survival (95.2% vs. 86.1%,P= 0.012) were obtained in the D3 + CME group. Multivariate COX regression revealed that D3 + CME was an independent protective factor for disease-free survival (P= 0.026).ConclusionD3 + CME could improve surgical and oncological outcomes simultaneously for right colon cancer compared to conventional CME. Large-scale randomized controlled trials were further required to confirm this conclusion, if possible.Graphical AbstractSupplementary InformationThe online version contains supplementary material available at 10.1007/s00464-023-10095-w.