Pancreatic cancer shows the worst prognosis among the solid tumors, and survival for patients with high-grade liver metastasis is estimated at around a few months. We reported the effects of combination therapy with gemcitabine and S-1 (GS therapy) on pancreatic cancer patients with high-grade hepatic metastasis. Patients with severe metastatic pancreatic cancer received chemotherapy comprising S-1 (30mg/m² p.o. b.i.d., days 1-14) and gemcitabine (1000mg/m² on days 1 and 8), repeated every 3 weeks. Fourteen patients (7 men, 7 women) received treatment at a mean age of 56.5 years (range, 39-76 years), achieving complete response in 1 patient, partial response in 5 patients, and stable disease in 3 patients and progressive disease in 5 patients. The response rate was thus 43%. Median progression-free survival was 186 days (95% confidence interval, 40-247 days). Median overall survival was 261 days (95% confidence interval, 162-358 days). GS therapy appears to be well-tolerated and effective in patients with high-grade hepatic metastasis.