Dissemination of gastric cancer may usually occur by direct spread through the perigastric tissues to adjacent organ, lymphatic spread, and hematogenous spread. We report a rare case of gastric cancer with mucosal metastastic lesion on the upper esophagus that was diagnosed by endoscopy and endosonography. A biopsy of the esophageal mass was performed and the pathologic findings with immunohistochemical stain for Mucin-5AC are proved to be identical to that of gastric adenocarcinoma, suggesting metastasis from main lesion of the gastric cancer. The lesion could not be explained by lymphatic or hematogenous spread,and its metastasis mechanism is considered to be different from previous studies. We suggest that the gastroesophageal reflux of cancer cells could be one of the possible metastatic pathways for metastasis of esophagus from an adenocarcinoma of the stomach. Dissemination of gastric cancer may usually occur by direct spread through the perigastric tissues to adjacent organ, lymphatic spread, and hematogenous spread. We report a rare case of gastric cancer with mucosal metastastic lesion on the upper esophagus that was diagnosed by endoscopy and endosonography. A biopsy of the esophageal mass was performed and the pathologic findings with immunohistochemical stain for Mucin-5AC are proved to be identical to that of gastric adenocarcinoma, suggesting metastasis from main lesion of the gastric cancer. The lesion could not be explained by lymphatic or hematogenous spread , and its metastasis mechanism is considered to be different from previous studies. We suggest that the gastroesophageal reflux of cancer cells could be one of the possible metastatic pathways for metastasis of esophagus from an adenocarcinoma of the stomach.