This is a first report of gastrectomy after nivolumab immunotherapy. We describe a case in an elderly woman with gastric cancer diagnosed with cT4bN3M1(LYM), cStage ⅣB disease. Although she was administered 2 courses of SOX chemotherapy as the primary treatment, she could not continue the treatment to due to bone marrowsuppression. The second-line treatment was weekly PTX therapy, but she experienced Grade 3 neutropenia and thrombocytopenia in the first course and could not continue treatment. Nivolumab as the next treatment was effective but was discontinued for suspected druginduced pneumonia. During that time, tumor hemorrhage occurred and we performed total gastrectomy. Postoperatively, nivolumab chemotherapy was resumed. There were no adverse events and the patient has had a continued partial response for 30 courses. Gastrectomy was necessary in this case, allowing observation of the pathological findings of this highly effective case.