A man in his 60s was admitted to our hospital with anemia. An endoscopic examination revealed advanced gastric cancer. CT revealed peri-gastric and para-aortic lymphadenopathy, and a nodular shadow(20mm)in the lower lobe of the right lung. PET-CT revealed abnormal uptake in the para-aortic lymph node and stomach wall and the nodular shadow in the right lung. A bronchoscopy revealed pulmonary adenocarcinoma. From the above, he was diagnosed with gastric cancer(cT4a, cN2, cM1, cStage IV )and lung cancer(cT2a, cN0, cM0, cStage I B). Because of gastric bleeding, we decided to operate on the gastric cancer before the lung cancer. First, total gastrectomy, splenectomy, and cholecystectomy were performed and then dissection of lymph node No. 16was performed. Histopathological examination indicated that lymph node No. 16was common to lung cancer, so the final diagnosis was gastric cancer(pT4a, pN0, cM0, fStage II A)and lung cancer(cT2a, cN0, pM1, fStage IV ). In this case, lymphadenectomy of No. 16in the first and pathological diagnosis during surgery could help us avoid splenectomy and cholecystectomy, and could reduce invasion.