Sentinel lymphadenectomy is an acceptable surgical technique for axillary staging among patients with clinically node-negative stage I or stage II breast cancer with primary invasive tumors measuring less than 5 cm. Patient selection and mapping team experience are critical factors for mapping success and accuracy. In the 2002 NCCN guidelines, exclusion criteria for sentinel node mapping include tumor multicentricity, the use of preoperative (neoadjuvant) chemotherapy or hormonal therapy, and a large excision (more than 6 cm) of the primary tumor performed before mapping. Future studies will clarify whether these exclusions are overly restrictive. Until then, the NCCN guidelines present a conservative perspective on sentinel lymphadenectomy, confirming that complete level I or level II axillary lymph node dissection remains the gold standard for breast cancer axillary staging.