The c-erbB-2 oncogene, which is a new human proto-oncogene similar to EGFR structurally, generates a glycoprotein of tyrosine kinase family with a molecular weight of 185,000 To evaluate the prognostic significance of c-erbB-2 oncogene expression in colorectal carcinoma, We analysed 73 colorectal carcinomas in paraffin sections immunohistochemically, using the monoclonal antibody specific for the c-erbB-2 oncogene product and correlated with clinicopathological data. The results were as follows 1) The immunoreactivity for c-erbB-2 oncogene was localized to cell membrane of the tumor cells and occasionally observed within the cytoplasm. 2) The positivity of c-erbB-2 oncogene expression was 71.2%(52/73) of the colorectal carcinomas overall. According to the histological types, the positivity of c-erbB-2 oncogene in adenocarcinoma(77.4%) was higher than that in mucinous carcinoma(36.4%)(p<0.05). 3) Expression of c-erbB-2 oncogene was significantly correlated with lymph node metastasis or distant metastasis(p=0.0117), Dukes stage(p=0.0432), and TNM classification(p=0.0102). These results suggest that c-erbB-2 oncogene expression may be used as a prognostic factor of colorectal carcinoma because of its correlation with other clinicopathological prognostic factors.