EMR is indicated for the treatment of superficial, early stage colorectal cancer. 1. The indications for EMR have expanded to include large tumors that spread laterally and circumferentially but that have a low risk of submucosal invasion, the so-called laterally spreading tumor (LST). 2. However, massive submucosal invasion can occur with LSTs, and factors such as an uneven-nodular surface, large nodules, large size, and aggressive histopathologic type necessitate further evaluation. 3. EMR has been performed as first-line treatment for LSTs based on these criteria and the pit pattern as determined by magnifying chromoendoscopy. 4. , 5. Bleeding is the most common complication of EMR. 6. It occurs in as many as 22% of cases; the risk is increased for lesions over 2 cm in size. 7. To reduce the risk of complications, a new technique for immediate and complete closure of large mucosal defects was developed and is described by the following case report.