Endoscopic methods such as endoscopic mucosal resection or endoscopic submucosal dissection (ESD) have been increasingly used for the treatment of gastric adenoma and early gastric cancer. Especially, ESD is very useful since it allows en bloc resection of large lesions. Bleeding and perforation are well known as common complications after ESD. However, there is no report of acute myocardial infarction associated with ESD. We report a case of acute myocardial infarction which was detected immediately after ESD.