Serum values of the tumor-associated antigen CA 19-9 are useful as an independent predictor of survival in patients with adenocarcinoma of the pancreas. However, the utility of biliary CA 19-9 values is unknown. This study was undertaken to determine whether biliary CA 19-9 levels are predictive of hepatic metastases. Between 1991 and 1996, thirty-eight patients treated for adenocarcinoma of the pancreas were evaluated using a biliary CA 19-9 assay. Bile was obtained from percutaneous stents placed during the perioperative period. Five of the 38 patients had low serum levels of CA 19-9 (<2 U/ml) and were excluded from the study. Twenty-seven (80%) of the 33 patients developed distant metastases: five pulmonary, five peritoneal, and 17 hepatic. Liver metastases were discovered initially in 10 and after resection of the primary tumor in seven (median interval 10 months). Biliary CA 19-9 values were significantly higher in patients with hepatic metastases (median 267, 400 U/ml; range 34,379 to 5,000,000 U/ml) compared to patients without metastatic disease (median 34,103 U/ml; range 6,620 to 239, 880 U/ml; P <0.006). Patients with hepatic, peritoneal, and pulmonary metastases had median survivals of 8,14, and 35 months, respectively (P <0.0041). All patients without metastatic disease are alive (median follow-up 13 months). Biliary CA 19-9 values are associated with a stepwise increase in the risk of developing metastatic disease. Patients with biliary CA 19-9 levels greater than 149,490 U/ml have an increased risk of developing recurrent disease in the liver and may warrant further hepatic evaluation or therapy.