Background: The histological detection of axillary lymph node tumor metastases in cases of breast carcinoma is of major prognostic significance, but may be difficult when metastases are of microscopic size. The micrometastases can be detected either by immunohistochemistry (IHC) or serial sectioning. Aims: We investigated whether immunohistochemical techniques and serial sectioning can increase the accuracy of metastatic detection and compared the efficacy of both. Materials and Methods: Thirty cases of breast carcinoma were studied in all of whom the axillary lymph nodes had been reported as free of metastases. Blocks from these cases were serially sectioned and stained with hematoxylin and eosin and a single section was stained with monoclonal antibody to cytokeratin AE1/AE3 and epithelial membrane antigen. The positivity for micrometastases was correlated with size, number, grade and histological type of primary tumor, lymph node size and number. Results and Conclusion: In 5/30 previously unsuspected cases, micrometastases were revealed by IHC and in 1/30 by serial sectioning. These findings suggested that serial sectioning is a labor intensive, time consuming and impractical procedure. Micrometastases were more frequently detected with age of patient >50 years, Grade 2/3 tumor, tumor size >5 cm and more than one primary tumor. Immunohistochemical analysis can be recommended as a routine procedure or an adjunct to routine histological procedures for the correct staging of breast carcinoma and use of adjuvant chemotherapy, especially in the high risk group.