Evaluation of axillary lymph nodes for metastatic involvement is the most significant factor in gauging prognosis in breast cancer patients. Complete axillary dissection can be associated with significant morbidity. Therefore, sentinel node biopsy was developed to sample nodes and avoid dissection in patients without clinical evidence of nodal involvement. While most surgeons currently perform the procedure, the technique remains unstandardized. Sentinel node identification rates, false-negative rates and procedural complication rates are the main outcomes measured and can depend significantly on variations in technique. Future studies on sentinel lymph node biopsy will probably focus on clarifying accuracy of the procedure in different clinical settings, delineating standard technical practice guidelines and further achieving improved outcomes.