Sentinel lymph node biopsy has been shown to be an accurate predictor of axillary nodal status in invasive breast cancer and is a useful alternative to axillary dissection for some patients. Because radioactive materials are often used to identify the sentinel lymph node, concerns have been raised regarding the safe handling of tissue specimens obtained by this technique. The Surgical Pathology Committee of the College of American Pathologists and the Association of Directors of Anatomic and Surgical Pathology have developed recommendations for the safe handling of radioactive specimens obtained by sentinel lymphadenectomy.