BACKGROUND: Polypectomy-associated bleeding is the most frequent complication of colorectal polypectomy. CASE PRESENTATION: An 82-year-old woman underwent polypectomy after an endoloop was placed in a pedunculated polyp in the sigmoid colon. However, the endoloop dislodged, causing massive bleeding from the stem surface. Furthermore, the bleeding vessel could not be identified because of the narrow resection surface and the presence of thrombus and hemorrhage. Therefore, several clips were removed, and polypectomy was performed again on the resection stem to open the resection surface wider and identify the bleeding vessels. Finally, the responsible arterial vessel appeared, leading to complete hemostasis. CONCLUSION: The additional stem resection may be a novel method for detecting uncontrolled bleeding after polypectomy for colorectal pedunculated polyps.