AbstractAxillary node status is the single most important prognostic factor for patients with primary breast carcinoma. During the last decade, one of the major advances in breast cancer has been the development of techniques that make axillary staging less morbid and more conservative. The sentinel lymph node (SLN) biopsy technique has received much attention as a possible alternative to axillary lymph node dissection (ALND). The SLN is defined as the first node in the regional lymphatic basin that receives drainage of the primary tumor. We will review the different techniques of lymphatic mapping for breast carcinoma, including radioactive and/or blue dye indicators, timing and site of injection, and preoperative lymphoscintigraphy. The SLN technique involves a multidisciplinary team. It is therefore important that each surgeon validate the technique in his or her own institution to ensure the successful and accurate assessment of the axilla. The SLN technique has modified the surgical management of breast cancer patients, although questions as to its safety have yet to be answered. Semin. Surg. Oncol. 20:214–223, 2001. © 2001 Wiley‐Liss, Inc.