We have experienced a case of Type 4 advanced gastric cancer with aplastic anemia, which had been treated with S-1 and intra-peritoneal docetaxcel combination chemotherapy followed by surgery. Fifteen years ago, a 51-year-old woman was diagnosed as aplastic anemia but she ignored any treatment due to no symptoms. A Type 4 advanced gastric cancer was detected with a chief complaint of stomach heaviness in December 2009. Peritoneal lavage cytology was performed before treatment and showed positive peritoneal dissemination. Two courses of S-1 and intra-peritoneal docetaxcel combination chemotherapy was administered but no serious side effects occurred during the therapy. Total gastrectomy with D2 lymph node dissection was successfully undergone. The final stage was ypT4aN3H0M0P1, Stage IV. It appeared that S-1 and intraperitoneal docetaxcel combination chemotherapy was a safe regimen for a patient with aplastic anemia in our case.