The extent of lymph node dissection necessary to optimize survival and minimize local recurrence in patients with melanoma of the trunk or lower extremity is not well defined. We reviewed the records of 420 patients undergoing superficial or combined superficial and deep groin dissection for melanoma. Prognosis depended on the extent of lymph node involvement rather than the extent of surgery performed. Node-positive patients undergoing elective lymph node dissection had an improved survival over those undergoing therapeutic lymph node dissection. In no subgroup of patients was more extensive lymphadenectomy associated with significant improvement in survival or alteration in pattern of recurrence. Dissection of the deep pelvic nodes in patients with melanoma appears to be of more prognostic than therapeutic value.