OBJECTIVE. Endoscopic submucosal dissection (ESD) of gastric neoplasia has been reported to have a higher bleeding rate than conventional endoscopic mucosal resection (EMR). The aim of this study was to identify the risk factors for bleeding associated with ESD. MATERIAL AND METHODS. The records of consecutive patients who underwent ESD for gastric adenoma/early gastric cancer were reviewed. Potential risk factors included patient age, lesion size, gross findings, location, and histology of the tumor. The primary end-point was the incidence of immediate or delayed bleeding related to ESD. RESULTS. A total of 144 patients were studied; bleeding occurred in 32 cases (22.2%) with immediate bleeding in 29 cases. Delayed bleeding (3 cases) occurred at day 2 (2 patients) and at day 7 in 1 patient. In all cases of immediate bleeding, immediate hemostatic therapy was successful. The histology of tumor was the only factor that was statistically significantly associated with bleeding (adjusted hazard ratio 6.770, 95% confidence interval 1.830-25.048, p=0.004). CONCLUSIONS. The only factor that correlated with an increased risk of bleeding with ESD was the presence of gastric malignancy. We found no factor that would, prospectively, be amenable to prevention of bleeding.