A 67-year-old man was referred to our hospital with a diagnosis of type 3 gastric cancer in lower third of the stomach. Computed tomography(CT)scan showed no distant metastasis, but peritoneal dissemination from gastric cancer. A laparoscopic exploration diagnosed pStage IV gastric cancer with peritoneal dissemination. Trastuzumab, capecitabine and cisplatin therapy was administered for initially unresectable gastric cancer. After 6courses of chemotherapy, primary lesion and lymph node metastasis shrank, and the peritoneal dissemination did not worsen by CT scan. The second laparoscopic exploration showed no apparent dissemination or metastatic cancer cells. Total gastrectomy with D2 lymph node dissection, partial colectomy and cholecystectomy were performed with curative intent. The pathological diagnosis was ypT3N1P0CY0, Stage II B, and the histological response of primary tumor after chemotherapy was categorized as Grade 1a. The patients is alive during 24 months after surgery with no evidence of recurrence.