Liver metastasis is the most common recurrence after curative surgery for colorectal cancer. Adjuvant chemotherapy such as hepatic arterial infusion or intensive systemic infusion may protect against metastatic tumor formation in the liver, but conversely have some adverse effects on patients. Therefore, the patients with a high risk of liver metastasis after curative resection should be selected for the chemotherapy. Portal blood samples of tumor drainage vein were obtained during operation from 148 colorectal cancer patients (Dukes' A: 41, B: 41, C: 33, D: 33) in our institutes from August 1998 to June 2001. Serum E-cadherin concentration (ng/ml) was estimated using an ELISA kit according to the manufacturer's instructions (Takara Shuzo Co.). After at least 6 months follow-up, each patient's status regarding recurrence was re-examined, as were the sites of any recurrences. Serum E-cadherin concentration in each Dukes' stage at the primary operation was as follows: A: 1,664.0, B: 1,974.6, C: 2,270.8, D: 3,123.1. In these follow-up periods, 21 patients developed metastatic tumor (liver: 13, extrahepatic: 8) and 95 did not. The average E-cadherin concentration in each group was as follows: liver: 3,585.6, extrahepatic: 2,261.8, no metastasis: 1,848.4 (p < 0.01 as shown in Figure 4). If the cut-off point is set at 3,000 ng/ml, liver metastasis can be predicted with sensitivity of 62.1%, specificity of 90.3%, and positive predictive value of 64.3%. High levels (> 3,000 ng/ml) of serum E-cadherin in portal blood may predict metachronous liver metastasis after curative surgery.