Carcinoembryonic antigen (CEA) immunohistochemistry was evaluated with 12 sections of male breast cancer diagnosed at Severance Hospital during the year of 1979-1990. Ten of twelve (83.3%) primary breast masses and four of five (80%) metastatic lymph nodes were CEA positive. There was concordance of CEA positivity and CEA positivity grade between primary mass and metastatic lymph nodes. The grade of CEA positivity did not appear to be related to size, tumor depth (T) and pathological stages. It was difficult to find a relationship between nuclear grade and CEA positive grade, because there was no nuclear grade 3 patient. Tumor heterogeneity was a constant feature of CEA staining with positivity varying from region to region.