Gastric mucinous adenocarcinoma is a rare histologic subtype of gastric cancers. It has been reported that the gross or endoscopic finding of mucinous gastric carcinoma is commonly described as a ulcerative or fungating mass in common. There has been controversy over the prognosis and the gross morphology of mucinous gastric adenocarcinoma. We report a case of mucinous gastric adenocarcinoma presenting as a submucosal tumor.