Carbohydrate antigen 19-9 (CA 19-9) is used as a serum tumor marker for adenocarcinoma of the upper gastrointestinal tract, particularly primary adenocarcinoma of the pancreas. In addition, this tumor marker can be highly elevated in benign diseases such as acute pancreatitis, chronic pancreatitis, chronic liver disease and biliary tract disease. A 69 year-old man was hospitalized with jaundice, cola-colored urine, right-sided upper abdominal pain, weight loss and pruritus. Laboratory data revealed a high level of serum CA19-9 of more than 100 000 U/mL and a mass in the left lobe of the liver was detected on computed tomography. ERCP, PTCA and CT-guided biopsy yielded the diagnosis of Klatskin tumor. Review of the literature revealed that Klatskin tumor with high levels of CA19-9 over 100 000 U/mL was not reported.