BACKGROUND/AIMS: Endoscopic en-bloc resection of the large colorectal lesions is technically difficult. The aim of this study is to evaluate the usefulness of combined endoscopic submucosal dissection (ESD) and snare resection for treating colorectal lesions. METHODS: We enrolled 23 patients (M:F=14:9, age range: 46~76 years) with 25 colo rectal tumors that were around or above 20 mm in diameter. A combined treatment of ESD and snare resection was performed. RESULTS: The mean size of the 25 lesions was 22.6+/-8.2 mm (range: 15.0~44.0 mm). Ten lesions were laterally spreading tumors and 15 lesions were found in the rectum. On the histopathologic examination, 16 lesions were adenocarcinoma, 2 lesions were villous adenoma, 1 lesion was a villotubular adenoma, 5 lesions were tubular adenoma and 1 lesion was a hyperplastic polyp. The mean resection time was 27+/-22 min (range: 10~91 min). En bloc resection was possible for 19 lesions (76%). Of these, 18 specimens showed clear resection margins and 1 showed a positive deep resection margin. Of the 6 piecemeal resection cases, 2 showed positive lateral resection margins. Therefore, an 88% tumor free resection rate was obtained. CONCLUSIONS: Combined ESD and snare resection may be an effective and safe modality for the resection of large colorectal lesions.