Abstract: In order to determine the status of estrogen recepor (ER) in the gastric cancer and colorectal cancer, 132 samples of gastric cancer and 68 colorectal cancer were assayed.ER were present in the 47 of the 100 (35.7 % ) patients with gastric cancer and in the 35 of the 68 (52 % ) patients with colorectal cancer.There is no significant difference between the sex and the ages.ER-positive were observed in Borrmann type 4, poorly sdifferentiated cancer and intrahepatic metastases were higher(p<0.05)" In 68 patients with colorectal cancer, ER-positive were observed in the rectum cancer, the left colon cancer higher than the right colon cancer.ER-positive were observed in well-differentiated cancer of colon higher than moderate-and poorly differentiated.There is no significant difference (P>0.05)" In this study the presence of receptors for estrogen in gastric cancers and colorectal cancers was confired.