91 Background: Gastric cancer is in the top three most common cancers in Vietnam and the disease is mainly detected in late stage. There is a lack of evaluation of the pre-neoplasia stage of gastric cancer and selection an appropriate and effective treatment remains still in debate. Hence, the study aims to evaluate, for the first time, the safety and efficacy of the application of endoscopic submucosal dissection (ESD) technique on Vietnamese patients with pre-neoplasia lesion in stomach. Methods: We included all patients diagnosed with lower or high-grade gastric dysplasia and hopitalized in the Department of Endoscopic and Functional Exploration in K Hospital from March 2018 to June 2019. Eligible patients were applied by the ESD technique as the standard treatment. We evaluated the efficacy and safety of after the intervention of ESD by the neoplasia recurrence rate after 3 months and the occurrence of adverse events during and after the ESD procedure described in frequency and percentage. Results: During the investigational period, we chose 65 pre-neoplasia gastric patients for the application of ESD technique. The male/female ratio was 1.09 and the mean age of patients was 58.07 years. The duration of hospitalization was about 3 days. We found 57 patients (87.69%) with location of the lesions in pylorus. The average of tumor sizes was 20.46 mm. All patients were treated with curative en bloc resection and no case was found as failure. Out of 65 patients, we found 2 patients (3%) with bleeding complication, no perforation and other post-surgery complication were identified. The average of procedure time was short (67.53 minutes). The histopathological specimen results revealed that 20 patients (30.76%) were diagnosed as cancer and 40 patients (61.53%) were diagnosed as high-grade dysplasia, all patients had a margin negative after ESD. After 3 months of treatment, all patients have no pre-neoplastic recurrence. Conclusions: Our result showed that the ESD technique is relatively safe and effective for Vietnamese patients with pre-neoplasia at stomach.