Herein, we report the case of 57-year-old woman who visited our hospital for abdominal distention, difficulty in walking, and edema of the legs in January 2012. She underwent gastroendoscopy, resulting in a diagnosis of advanced gastric cancer of the pyloric antrum. A diagnosis of unresectable advanced gastric cancer was made because computed tomography (CT) showed the presence of ascites (suspected to indicate peritoneal dissemination), para-aortic lymph node metastases, and brain metastases. Stenting was performed for pyloric stenosis and cell-free and concentrated ascites reinfusion therapy (CART) was administered to facilitate oral intake. We administered two courses of chemotherapy with weekly paclitaxel. However, CT showed the presence of ascites and growth of the main tumor in the first month after the initiation of chemotherapy. We performed CART, and treatment was changed to S-1/paclitaxe(l 5 courses). Ascites decreased markedly and activities of daily living improved. However, 11 months after the initiation of therapy, the patient died.