Objective: Sentinel lymph node (SN) examination is the current procedure to establish the status of axillary lymph nodes in breast cancer. To avoid a two step delayed surgical procedure, a reliable and quick method of SN evaluation is advocated. Rapid immunohistochemical technique (UICH) for keratin has been only recently proposed. Aim of this study is to apply keratin UICH in frozen sections (FSs) of SNs. Method: A consecutive series of 231(Series A) SN cases was studied at FS level followed by two sections stained with keratin UIHC. All procedure requires 23 min. For comparison 131 consecutive cases (series B) of SN were studied with FS only. All residual tissue from both series was paraffin embedded (PS). Results: Series A: SNs showed tumour involvement in 41 cases (17.7 %). In only 8 cases (3.75 %), PS sections evidenced additional neoplastic cells (micometastases) not seen with keratin UIHC, that led to a delayed axillary dissection. Series B: PS sections revealed metastatic deposits (micrometastases) not seen in FS in 6.1 % of cases. Conclusion: FS coupled with keratin UHIC of all the entire lymph node accurately evidences carcinoma cells in SNs.