The surgical management of breast cancer has changed dramatically from a deforming ablative procedure to an approach that for the majority of breast cancer patients can preserve the breast and axillary anatomy. The current approach to the diagnosis of breast cancer and the evolution of the more limited approach to surgical resection are discussed. The technique of sentinel lymph node biopsy, originally developed for melanoma patients, has now been adopted for use in the treatment of breast cancer. The methodology and advantages of this approach to the axillary lymph nodes in both tumor recognition and reduced risk to the patient are detailed.