Introduction <p>The incidence of delayed bleeding after endoscopic mucosal resection (EMR) of colorectal tumors has been reported to be approximately 1.1–1.7%. Some studies have shown that clipping after EMR does not significantly reduce delayed bleeding. Delayed bleeding after colorectal EMR with clips often occurred due to gaps in the clips or the detachment of mucosal areas that were heavily affected by coagulation.</p> Methods <p>To prevent this complication, the perfect closure (PC) technique, with conditions such as secure clipping closely together without any gaps, including not only the ulcer but also the coagulated mucosa as the suture range, and avoiding “clip-on-clip” placement as far as possible, is considered important against delayed bleeding after colorectal EMRs. In this study, in order to verify the usefulness of the PC technique, we conducted a prospective study of patients who underwent PC after colorectal EMR was performed in two clinics and three hospitals.</p> Results <p>1744 lesions (1133 patients) were evaluated. No post-procedural bleeding occurred in any patient. The average number of clips used for one lesion was 4.71 ± 2.04, and the average tumor diameter was 8.0 ± 3.78 (5–26) mm. The rate of post-procedural bleeding was 0%.</p> <p>In addition, the analysis of the results using a Monte Carlo simulation showed medical and economic advantages compared to previous studies in which clip closure was performed after colonic EMR.</p> Conclusion <p>PC has the potential to be an excellent method for preventing postoperative bleeding after colorectal EMRs.</p> Graphic abstract <p></p>