We report a case of long-term survival of 5 years after operation and chemotherapy for type 4 gastric cancer with peritoneal dissemination. A 41-year-old woman underwent total gastrectomy for type 4 gastric cancer with peritoneal dissemination and pancreas invasion. After operation, chemotherapy with S-1 plus PSK therapy, S-1 plus CDDP, and S-1 plus DOC was performed. The regimen of S-1 plus CDDP included S-1 on day 1-5, 8-12, 15-19, 22-26 and 2 weeks rest and PSK daily. After S-1 plus PSK therapy(34th course), peritoneal recurrence caused ileus, so a right hemicolonectomy was performed. Now the patient is undergoing weekly paclitaxel. The S-1 plus PSK therapy is able to prolong time to progression and has fewer adverse effects.