A better understanding of the locoregional and systemic approaches to breast cancer over the past decade and one-half has altered the perspective on surgical management of the axilla. An increased awareness of the importance of early diagnosis and appropriate staging has focused further attention on the extent of resection of axillary lymph nodes. Examined here are the anatomy and physiology of the axillary lymph nodes, their clinical evaluation, the significance of histologic evaluation, a discussion of the procedure's role in staging and therapy, and a presentation of the complications of axillary lymph node dissection. It is in this light that we discuss the extent of axillary lymphadenectomy in early diagnosis of breast cancer.