Background: Endoscopic submucosal dissection (ESD) of gastric tumors in the mid to upper stomach is a technically challenging procedure. This study compared the therapeutic outcomes and adverse events following ESD of tumors in this area, performed in conjunction with either general anesthesia (GA) or monitored anesthetic care (MAC).Methods: Between 2012 and 2018, 674 patients underwent ESD of gastric tumors in the midbody, high body, fundus, or cardia (100 patients received GA; 574 received MAC). The results were analyzed using propensity score (PS)-matched (1:1) patients receiving either GA or MAC.Results: PS matching identified 95 patients who received GA and 95 matched patients who received MAC. Both groups showed high rates of en-bloc resection (GA, 98.5%; MAC, 98.9%; p = 0.18) and complete resection, defined as tumors excised with histologically confirmed negative margins (GA, 82.1%; MAC, 90.5%; p = 0.14). There were no significant differences in the frequencies of adverse events (GA, 16.8%; MAC, 9.5%; p = 0.13) between the anesthetic groups. A logistic regression analysis indicated that the anesthetic method was not a factor impacting the frequencies of complete resection or adverse events. Conclusion: At our high-volume center, good therapeutic outcomes were achieved following ESD of tumors in the mid to upper stomach, regardless of the anesthetic method used. Our results demonstrate the efficacy and safety non-inferiority of the ESD procedure performed in conjunction with MAC, compared with GA.