Background/aims: Colorectal laterally spreading tumors are superficial tumors classified into two groups as granular (G-laterally spreading tumor) and non-granular (non-granular-laterally spreading tumor) types. In this study, we aimed to investigate the efficacy and feasibility of endoscopic submucosal dissection in the treatment of laterally spreading tumors. Materials and Methods: Forty-four laterally spreading tumors in 40 patients were treated with endoscopic submucosal dissection at a tertiary referral hospital. Patient data were collected retrospectively. In this study, we evaluated tumor size, macroscopic type, lesion location, histology, curative resection, and complications. Results: Of the 44 laterally spreading tumors excised by endoscopic submucosal dissection, 29 (65.9%) were G-laterally spreading tumor and 15 (34.1%) were non-granular-laterally spreading tumor. Most of the non-granular-laterally spreading tumors were localized in the right colon, while most G-laterally spreading tumors were localized in the left colon (p<0.001). There was also no difference between G-laterally spreading tumors (6/29) and non-granular-laterally spreading tumors (2/15) with regard to exhibiting malignant features (p=0.69). Although median size (40 mm vs. 27.5 mm) and procedure time (115 minutes vs. 60 minutes) for G-laterally spreading tumors were bigger and longer respectively, procedure time per cm(2) was not different (8.9 minutes vs. 8.2 minutes) between the two groups. Curative resection rates for laterally spreading tumors were quite high (95.5%), while en bloc resection rates were low (77.3%). The rates of endoscopic submucosal dissection-related complications such as perforation, major and minor bleeding were low (4.5%, 2.3%, 6.8%, respectively). Conclusion: Endoscopic submucosal dissection is an effective and safe therapeutic option with high curative rates for early-stage malignant and pre-malignant laterally spreading tumors not having an absolute indication for surgery, regardless of the lesion type and size.