We review 7 cases of cancer in the reconstructed gastric tube after resection for esophageal cancer in our hospital. From this experience, we report 2 cases which were resected curatively by endoscopic or open surgery. Case 1, a 61-year-old man received a subtotal esophagectomy reconstructed by a gastric tube, retromediastinally. 85 months after operation, cancer in the gastric tube was detected endoscopically, and partial resection was performed. Case 2, a 75-year-old man received subtotal esophagectomy reconstructed by a gastric tube via a retro-mediastinal route. After 104 months, early cancer in the gastric tube was diagnosed and we performed endoscopic mucosal dissection (ESD). Long-term follow-up by regular endoscopy is necessary in patients after esophageal surgery to screen for cancer in the reconstructed gastric tube.