A 70-year-old woman diagnosed as having cancer of the esophago-gastric junction (EGJ) . She had intermittently received treatment with a proton pump inhibitor (PPI) for over 10 years for gastro-esophageal reflux disease (GERD) . As her symptoms were extremely severe 3 years ago, we decided to repeat a course of her PPI treatment. Endoscopic examination carried out 7 months prior to the surgery revealed a type 0-Is lesion at the EGJ, which was confirmed as Group 2. Thereafter, a repeat endoscopy performed 2 months prior to the surgery revealed that the tumor had progressed to Group 4. The palisade vessels characteristic of Barrett’s esophagus were not recognized in the distal portion of the esophagus. Due to suspected sm invasion by the tumor, a laparoscopic proximal gastrectomy was performed. The resected specimen showed a tumor that was Type 0-Is, 2.0 × 1.5 cm, tub1, sm, v0, (Stage IA) . Although Barrett’s esophageal cancer was strongly suspected based on the clinical data, histopathology failed to reveal Barrett’s epithelium in the vicinity of the carcinoma lesion. This could be due to the short length of the resected specimen. EGJ cancer should be carefully resected and examined, bearing in mind the diagnosis of Barrett’s esophageal cancer.