BACKGROUND/AIMS: Endoscopic submucosal dissection (ESD) has been widely performed. However, procedure related-complications and the risk of tumor recurrence are limitations. We analyzed the clinicopathological characteristics of patients who underwent curative additional gastrectomy (gastrectomy) after ESD. METHODS: The clinical characteristics of cases underwent gastrectomy after ESD were retrospectively analyzed. RESULTS: Between January 2002 and August 2010, 1,512 cases underwent ESD for early gastric cancer (n=511) or adenoma (n=1,001). Thirty-two cases (2.1%) underwent gastrectomy after ESD. Thirty cases (2.0%) were EGC and 2 cases (0.1%) were adenoma. Extended indication, larger tumor size and piecemeal resection were risk factors for gastrectomy after ESD. According to the causes of gastrectomy, 13 cases underwent gastrectomy due to complications (40.6%; bleeding in 9, perforation in 4), and 19 cases based on pathological results (incomplete resection in 13, lymphatic invasion in 6). In cases with incomplete resection, the rate of residual tumor and lymph node metastasis after gastrectomy was 69.2% (75% lateral margin, 60% deep and 75% both) and 7.7%, respectively. Three (50%) of the 6 cases with lymphatic invasion had lymph node metatstasis. CONCLUSIONS: The causes of gastrectomy after ESD were the procedure-related complications, the incomplete resection and lymphatic invasion. For complete and curative ESD, endoscopists should try to minimize complications and determine the depth of invasion accurately before ESD.