Sentinel lymph node (SLN) biopsy is effective to assess axillary nodal status and avoiding axillary lymph node dissection (ALND) in patients with clinically node-negative early stage breast cancer. No standardization of the technique has yet been established. This review discusses the feasibility, the accuracy and the different techniques for this procedure. Although the SLN can be successfully identified by either the dye or gamma probe-guided method, its identification is facilitated when the two techniques are combined. To increase the sensitivity of the pathological examination of the SLN, it is necessary to make multiple step sections with hematoxylin and eosin staining immunohistochemistry on permanent sections. The intraoperative frozen sections and imprint cytology examinations of the SLN may be useful in determining its status, but further studies are needed to establish their performance. In clinical practice, routine ALND can be avoided for small tumours when the multidisciplinary team has an extensive experience of this technique. However, long-term regional control and survival have to be studied in prospective randomised trials, before SLN biopsy can replace routine ALND as the preferred staging method for women with localized breast cancer.