A 52-year-old man was initially diagnosed with an unresectable acinar cell carcinoma of the pancreas with liver metastasis and involvement of the superior mesenteric artery. After 5 courses of systemic chemotherapy(gemcitabine and S-1), the size of the pancreatic tumor had decreased from 31mm to 19mm and the liver metastasis had disappeared. We initiated chemoradiotherapy( CRT: S-1+56 Gy)for further local treatment. After CRT the size of the pancreatic tumor decreased to 13mm and his serum CA 19-9 level decreased from 677.2 U/mL to 38.1 U/mL. After 2months of S-1 administration, we performed subtotal stomach-preserving pancreaticoduodenectomy with D2 lymph node dissection. Histopathological examination revealed that most of the pancreatic cancer was replaced by fibrosis and only a few atypical epithelial cells existed. No cancer cells were found at the surgical margin. The patient remains alive without any signs of recurrence 59 months after the systemic chemotherapy and 51 months after the surgical resection.