The use of sentinel lymph node biopsy (SLNB) has revolutionized breast surgery for early stage breast cancer. SLNB accurately stages the axilla without the morbidity of axillary lymph node dissection (ALND). While allowing those patients with No disease to avoid a potentially morbid dissection, SLNB is a diagnostic procedure which identifies nodal disease and is not designed to replace ALND in patients with metastatic disease in the axilla. ALND provides regional disease control, assists physicians in making decisions for patients regarding systemic therapy, and may or may not have a survival advantage. The American College of Surgeons Oncology Group Z0011 study was constructed to determine whether there was a survival difference between completion ALND vs. observation in patients with a positive sentinel lymph node (SLN). Without strong data from randomized, controlled trials regarding the locoregional and long-term survival of patients who undergo observation after a positive SLN, patients should be offered completion ALND for a positive SLNB although ALND may offer no survival advantage.