Malignant transformation of heterotopic pancreas is extremely rare. We report a case of ductal adenocarcinoma arising from heterotopic pancreas in the stomach of a 64-year-old man. Preoperative CT scans showed the lesion as a submucosal mass along the greater curvature of the pyloric antrum and protruding into the pyloric canal. After gastric surgery, the resected tumor was histopathologically diagnosed as a ductal adenocarcinoma arising from heterotopic pancreas with cystic dilatation of aberrant pancreatic duct.