Correlation between CEA and CA19-9 levels of peripheral and draining venous blood, and 12 histopathologic and immunohistochemical variables, was examined in 108 patients with colorectal cancer. CEA levels of draining blood (mean 62.7 ng/ml and positive rate greater than 5 ng/ml, 63.9%) were significantly higher than those (16.3 ng/ml and 31.5%) of peripheral blood. However, CA19-9 levels (mean 576 U/ml and positive rate greater than 37 U/ml, 29.5%) of draining blood were not different from those (568.0 U/ml and 29.5%) of peripheral blood. Histochemically, CEA was observed in all of the 83 specimens and distributed in almost of all cancer cells, although CA19-9 was found in 52 (62.5%) of 83 specimens and focally localized in some part of cancer lesions. Elevation of CEA levels in draining and peripheral blood was most highly correlated with grade of venous invasion and its layer of colorectal wall. While, elevation of CA19-9 levels in both draining and peripheral blood was most highly associated with grade of lymphatic invasion and node metastasis. CEA levels of peripheral blood was negative in 9 (47.4%) of 19 patients with liver metastasis. However, the levels of draining blood was negative only one (5.3%) of these patients and the mean value (273.6 ng/ml) was much greater than that (59.6 ng/ml) of peripheral blood. These results suggest that CEA may be haematogenously drained by the portal system via the draining vein from the cancer cells in the invasive veins, and that CA19-9 may be drained by the thoracic duct of lymphatic system. It is also suggested that the measurement of CEA, especially in draining blood, and CA19-9 may be available to predict the metastasis and/or recurrence of different organs such as the liver, lymph node and so on.