Carcinoembryonic antigen (CEA) has been detected by immunohistochemistry in breast carcinoma, but its relationship with prognosis is still unclear. This difficulty may be because of the great variety of antibodies used for its determination. In the present study, 271 stages I and II breast carcinomas are analyzed by immunohistochemistry, using T84.66 antibody, a well-known highly specific CEA antibody. The results show that CEA expression was not associated with any of the clinicopathologic factors analyzed. Factors associated with disease-free survival (DFS) after univariate logistic regression analyses were tumor size smaller than 2 cm (P = .01), lymph node free of metastases (P = .0000), low nuclear grade (P = .007), absence of c-erbB-2 overexpression (P = .02), and bcl-2 (P = .005) and CEA expression (P = .005), whereas those significantly associated with a better overall survival (OS) were tumor size small than 2 cm (P = .002), lymph node free of metastases (P = .0001), low nuclear grade (P = .01), low histological grade (P = .02), absence of c-erbB-2 overexpression (P = .002) and bcl-2 expression (P = .01). After multivariate stepwise regression analysis, lymph node free of metastases (P = .0000), CEA expression (P = .001), absence of c-erbB-2 overexpression (P = .01), and bcl-2 expression (P = .01) were found to be independent factors associated with DFS, whereas lymph node free of metastases (P = .0000), tumor size smaller than 2 cm (P = .0000), and absence of c-erbB-2 overexpression (P = .004) were associated with a better OS. These results show that immunohistochemical detection of CEA with the antibody T84.66 may be useful as an additional factor in establishing breast cancer prognosis.