Abstract: This paper reports the results of immunohistochemical localization in colorectal carcinoma and adenoma by anti-human gastric carcinoma monoclonal antibody MG7.One hundred and twelve cases of colorectal carcinoma, 96 cases of surround-ing mucosa, 46 cases of adenoma and 14 cases of normal colonic mucosa wereexamined. One hundred and six of 112 cases of colorectal carcinoma were positivelystained (94.64%) and strong staining could be observed in 102 of 106 cases(96.23%). One of 14 cases normal colonic mucosa was only weak positive. Seventeen of46 cases adenoma revealed positive staining which was often associated with dys-plasia.These results suggest that MG7-associated antigen in human colorectal car-cinoma is abundant and relative specific antigen.