Correlation between CEA and CA19-9 levels of peripheral and draining venous blood, and 11 histopathologic and 2 immunohistochemical variables, was examined in 53 gastric cancer patients. CEA levels of draining blood were significantly higher than those of peripheral blood in 48 patients with CEA producing cancer. CA19-9 levels of draining blood were not different from those of peripheral blood in 33 patients with CA19-9 producing cancer. Elevation of CEA levels in the blood was most highly correlated with venous invasion, though the levels in draining blood were related to other 10 variables except tumor location and CEA distributed patterns of cancer lesions. These 10 variables relating to CEA elevation were highly associated with venous invasion. However, tumor location and CEA distributed patterns were not associated with venous invasion. While, elevation of CA19-9 levels in the blood was most highly correlated with lymphatic invasion and node metastasis, though the levels were related to the almost same variables which were highly associated with lymphatic invasion and node metastasis as CEA elevation-relating variables. These results suggest that CEA may be hematogenously drained by the portal system via the draining vein from the CEA producing cancer cells in the invasive veins, and that CA19-9 may be drained by the thoracic duct of lymphatic system.