Treatment of the axilla with either radiotherapy or surgery remains an integral part of the management of patients with invasive breast cancer. In general, the standard treatment of the axilla involves a partial ALND (surgical clearance of axillary nodes from levels I and II). There is as yet no evidence that axillary treatment improves survival, but the issue remains controversial. Axillary lymph node dissection is an effective staging procedure and is essential for local control of disease in the axilla, although, with increased emphasis on mammographic screening and early detection, the incidence of node-positive breast cancers is decreasing. Today, only about 30% to 40% of all invasive breast cancers are node-positive. Thus, in most cases, the potential morbidity of ALND could be avoided if the status of the axillary nodes were ascertained with a less invasive procedure. The SLNB may eventually prove to be a preferred alternative to routine ALND. It must first be demonstrated, however, that SLNB (without completion ALND) does not adversely affect outcome. Randomized controlled trials must address these concerns, and surgeons must await completion of these studies before accepting SLNB as the standard of care.