Lymphatic mapping and sentinel lymph node (SLN) biopsy have changed the standard of care for patients with malignant melanoma, by providing a less morbid procedure to obtain the nodal staging information that is critical for therapeutic decisions. Detailed examination of the SLN identifies patients who have an increased risk for recurrence and death. Patients whose melanoma is upstaged with very sensitive assays based on reverse transcriptase polymerase chain reaction technology are better targeted for clinical trials or surgical or adjuvant therapies. In the future, melanoma may be "ultrastaged" by examining the SLNs, peripheral blood, and bone marrow. This may improve identification of patients who are surgically cured of their disease and therefore can be spared the side effects of more radical surgery or the toxicities of adjuvant therapy. The lymphatic mapping procedure is the most accurate way to determine the tumor status of the regional lymph nodes.