A 62-year-old man was revealed to have type 2 gastric cancer with synchronous liver metastasis. We considered liver metastasis to be a prognostic factor, and performed two courses of combination thermochemotherapy consisting of hepatic arterial infusion of MMC and TS-1 and thermotherapy. Partial response was observed in the liver metastases,but the primary lesion showed no changes; therefore, we performed four courses of combination thermochemotherapy consisting of TS-1/CDDP therapy and thermotherapy. By the end of three courses of this therapy,the primary lesion had cicatrized,and endoscopic biopsy revealed no cancer cells. These results suggest that gastric cancer,in which liver metastasis is considered to be a prognostic factor,can be effectively treated by combination therapy with hepatic arterial infusion therapy, followed by thermochemotherapy for the primary lesion.