Thermochemotherapy was performed on gastric cancer cases of hepato-metastasis. The subjects were 12 gastric cancer cases having hepato-metastatic lesions (10 synchronous, 2 heterochronous). Using 8 or 13.58 MHz-dielectric heating apparatus, thermotherapy was carried out for 40-60 min (twice a week, 5-35 times, averaging 12.8 per case) at an intra-tumoral temperature greater than 42 degrees C. Chemotherapy consisted of hepato-arterial infusion of MMC 10 mg/BW, CDDP 75 mg/m2 once per 3-4 weeks and consecutive daily administration p.o. of UFT 800 mg/BW. Effect greater than PR was noted in 75% (9/12) on the whole and in 100% (5/5) and 57% (4/7) for H1-2 and H3, respectively. Mean and 50% survival periods were 9.3 and 7.2 months, respectively, with a one-year survival rate of 38%. Chemotherapy-induced side effects were nausea and vomiting in 83% and leukopenia and thrombopenia in 67%, while the only thermotherapy-induced side effect was subcutaneous fatty tissue necrosis in 3 cases. The above results suggested the effectiveness of the present thermochemotherapy in the treatment of hepato-metastasis of gastric cancer.