A 47-year-old man with chronic hepatitis B had progressive elevated oc-fetoprotein of 2 years' duration. A pancreatic tail tumor, instead of liver tumor, was detected. He underwent elective distal pancreatectomy and splenectomy and the pathology turned out to be acinar cell carcinoma of the pancreas. Serum level of oc-fetoprotein returned to normal soon after surgery. No cancer recurrence was noted after 3 years of follow-up. Alpha-fetoprotein is commonly used as a tumor marker to screen for hepatocellular carcinoma in high-risk patients. However, elevated oc-fetoprotein could occur in a much rarer disease, acinar cell carcinoma of the pancreas.