The status of the axillary lymph nodes is one of the most important prognostic factors in women with early stage breast cancer. Histologic examination of removed lymph nodes is the most accurate method for assessing spread of disease to these nodes. Axillary lymph node dissection (ALND) remains the standard approach for women who have clinically palpable axillary nodes. The benefits of ALND include its impact on disease control (axillary recurrence and survival), its prognostic value, and its role in treatment selection. However, the anatomic disruption caused by ALND may result in lymphedema, nerve injury, and shoulder dysfunction, which compromise functionality and quality of life. For patients who have clinically negative axillary lymph nodes, sentinel lymph node (SLN) biopsy offers a less morbid method to determine if there are positive nodes, in which case axillary node dissection would be necessary. Patients who are SLN-positive should undergo complete ALND. Axillary reverse mapping (ARM) is a recent improvement of ALND which, like the biopsy of the GS, would reduce morbidity.