Axillary nodal status continues to be the most statistically significant predictor of survival for patients with breast cancer. Although still providing regional control of axillary disease, axillary dissection is more important as a staging and prognostic tool. Trials are currently underway to investigate the possibility of replacing the current standard treatment of breast cancer, axillary lymph node dissection, with the less invasive lymphatic mapping and sentinel lymph node biopsy. This issue and the technical aspects of sentinel lymph node mapping for breast cancer are discussed in detail in this article.