Immunoperoxidase staining was used to examine carcinoembryonic antigen (CEA) expression in 167 breast cancer cases. Patients with histological evidence of regional or localized breast cancer who lived less than 3 years or greater than 10 years were assessed. Overall expression of CEA was 65%. There was no significant correlation in CEA expression and survival in either regional or localized breast cancer cases. There was no association between CEA expression and number of lymph nodes involved, size of tumor, parity, gravidity, blood type, or menopausal status of the patients in either group. When the lymph nodes of cases with regional breast cancer were examined, there was a statistically significant number of short survivors whose primary tumor was negative for CEA, but whose metastatic tumor expressed the marker when compared to long survivors with regional lymph node involvement.