Intraoperative lymphatic mapping (ILM) with a radiopharmaceutical is a nuclear medicine examination which identifies for the surgeon the first lymph node to receive lymphatic flow from the primary tumor site. This node is removed and analyzed for the presence of malignant cells. By locating the lymph node prior to surgery, a small incision can be used to remove the node and a smaller dissection can be employed. The high negative predictive value of the technique seems to provide an accurate staging procedure and may spare patients who are lymph node negative the morbidity of a complete lymph node dissection. Consequently, staging of melanoma by lymph node mapping and biopsy may be equivalent to regional node dissection without the attendant post surgical morbidity.