We set out to determine whether carcinoembryonic antigen (CEA) levels in gallbladder bile and serum can predict metachronous liver metastasis of colorectal cancer. At the time of surgery, gallbladder bile and serum were sampled for enzyme immunoassays of CEA. Upper limit (mean +/- 2SD) of the normal range for CEA in bile was established from samples at surgery for nonneoplastic gallbladder disease. In 11 patients with synchronous liver metastases, biliary CEA levels correlated with the size of hepatic lesions. In 49 patients without evident liver metastases at the time of surgery, elevated biliary CEA levels predicted subsequent emergence of metachronous liver metastases with 75% sensitivity, 85% specificity, and 84% accuracy; serum CEA levels were not a reliable predictor. In conclusion, determination of biliary CEA level at the time of colorectal resection shows promise as a way to identify patients at high risk for hepatic recurrence.