We report a rare case of metastatic colon cancer that occurred after gastric cancer surgery. The patient was a 63-year- old man who had received distal gastrectomy for type 2 advanced gastric cancer, which was a moderately differentiated adenocarcinoma, pT4a (SE),pN0, P0, CY0, M0, and Stage IIB. He was treated with S-1 for 1 year after the operation. However, levels of CA19-9 gradually increased postoperatively. Subsequently, 2 years and 10 months after the operation, computed tomography indicated a mass in the transverse colon. Colonoscopy showed half-circumferential stenosis in the transverse colon. The histopathological diagnosis was metastasis of gastric cancer. We performed right-hemicolectomy. Histopathology showed a moderately or poorly differentiated adenocarcinoma, which was colonic metastasis of the gastric cancer. After the operation, he was treated with paclitaxel weekly. Our findings suggest that after surgery for gastric cancer, it is worthwhile to monitor for metastatic colorectal cancer.