Gastrointestinal carcinomas represent the most common cancers worldwide. The coexistence of gastric cancer with metachronous colon cancer represents a rare phenomenon, and the prognosis of the patient is poor. We present here a case of an elderly patient with primary gastric intestinal type well-differentiated adenocarcinoma (pT3N0, stage IIA) who developed a metachronous right-sided colon cancer diagnosed and treated after 11 years from the first surgical intervention. Histopathological and immunohistochemical examination revealed a well-differentiated adenocarcinoma (strongly positive staining for cytokeratin 20 and CDX2), pT3N0 stage IIA. The patient is still alive and active after 16 years from his first surgical intervention, even though no treatment has done after the removal of his second cancer. In conclusion, in any case of gastric cancer, first the surgeon, and then the general practitioner should be alert to recognize a second primary tumor with different origin and to perform complete postoperative control. The correct diagnosis could lead to the patients' best prognosis.