Delayed perforation occurring after endoscopic submucosal dissection (ESD) is a rare but serious complication which sometimes requires emergent surgery. However, reports of its characteristics, including endoscopic imaging and management, are not fully detailed. A 70-year-old woman was referred to our hospital for the treatment of early gastric cancer. On the day of the ESD, hematemesis was observed because of a Mallory-Weiss tear, and a visible vessel in the post-ESD ulcer was additionally treated endoscopically by coagulation. Second-look endoscopic examination on the next day revealed a perforation 3 mm in diameter at the treated vessel in the ulcer. The shape of the perforation was round and the color of the surrounding muscle layer had become whitish. The perforation was closed with endoclips, and decompression of the pneumoperitoneum was performed. The patient was conservatively managed and was discharged 13 days after the ESD. We show endoscopic images of delayed perforation and discuss the mechanism and management of this complication.