Sentinel lymph node biopsy for breast cancer has been introduced in the mid-1990s and it has now been performed on thousands of patients. Although this procedure has not been validated by randomised clinical trials, it has been rapidly adopted around the world by surgical specialists in clinical practice as a diagnostic procedure instead of the axillary lymph node dissection. The critical issue in sentinel lymph node biopsy is the false negative results which could expose the patients to axillary recurrence and lead to understaging and incorrect adjuvant therapy decisions. The current problem is to perfect the procedure for an optimal use in routine reducing this risk of false negative results. This false negative rate declines sharply when the technique is performed in selected patients by experienced surgeons using a combined detection. In this article, we review the technical aspects and results of the sentinel lymph node biopsy in breast cancer and discuss the recommendations for the optimal clinical practice.