Abstract: Colon carcinoma-associated antigen(CCA)was detected with sandwich ELESA method in sera of 74 cases of patients with malignant tumors and 78 cases of patients with other diseases.Total sensitivity was 51.35% in all of the maligancy in which, gastrointestinal carcinoma was of 72. 97%, primay long carcinoma 32.14%.Total specificity was 91.03% in all of the benign diseases.These results showed that although the CCA that IG10 monoclonal know is not specific tumor marker of gastrointestinal carcinoma,the CCA is better tumor marker from the sera positive rate of gastrointestinal carcinoma. The sensitivity could be raised when CCA and CEA are detected in the patients sera in same time.