The prognosis of esophageal carcinoma has improved, but along with this improvement, concern has increased about the occurrence of second primary carcinoma, especially gastric carcinoma, in tubes constructed from the stomach after esophagectomy. We describe our experience in the diagnosis and treatment of gastric tube carcinoma. We retrospectively examined 31 cases of gastric tube carcinoma; these cases occurred in 26 patients who received esophagectomy between September 1968 and October 2000. Surgical resection was performed in 10 patients. Gastrectomy with regional lymph node dissection was performed in 7 patients and partial resection of the stomach without lymph node dissection in 3 patients. In 6 patients leakage was encountered after gastrectomy; 3 of these patients died of multiple organ failure. Only one of the gastrectomy patients is alive without disease. Over the past 7 years, 15 patients with 20 lesions have been treated by endoscopic mucosal resection (EMR). Three of these patients required additional operation because of massive submucosal invasion by the tumor. One complication occurred at EMR, but it was successfully treated by conservative therapy. All patients treated by EMR alone were alive with neither local nor distant metastasis during a median followup period of 27.5 months. Of those patients who received surgical resection initially and were diagnosed as inoperable, all 10 had not received periodic checkups and had some symptoms. In contrast, of 15 patients who underwent EMR, all 20 lesions were found by annual followup endoscopic examination in the absence of symptoms. EMR for gastric tube carcinoma is safe and has few complications, in contrast to surgical resection of the gastric tube, which places a severe burden on the patient and has high morbidity and mortality. Early detection of the tumor by annual endoscopic examination is recommended for achieving good outcomes in gastric tube carcinoma after esophagectomy.