OBJECTIVE Gastric cancer in the remnant stomach after proximal gastrectomy has not been studied in detail. The aim of this study was to clarify the incidence of this type of cancer. METHODS From 478 cases of radical proximal gastrectomy followed prospectively, those that developed gastric cancer in the remnant stomach were identified. The incidence of gastric cancer in the remnant stomach in the cohort was compared with the expected incidence of gastric cancer in the general population. RESULTS Gastric cancer in the remnant stomach occurred in 8 (6 males, 2 females) of 478 patients (1.7%). The duration from primary gastrectomy to gastric cancer in the remnant stomach detection was over 10 years in 3 cases. In males, the rate of the incidence of gastric cancer in the remnant stomach was lower than the expected incidence for all durations. In females, the rate was also low, but appeared slightly elevated from 6 to 10 years and from 16 to 20 years after the primary gastrectomy. CONCLUSIONS The incidence of proximal gastrectomy after proximal gastrectomy is not high, and the risk in males is especially low. However, proximal gastrectomy may develop over 10 years after surgery, and long-term follow-up is essential.