A mediastinal lymph node dissection as opposed to lymph node sampling should be an integral part of the operation in all patients with resectable lung cancers. A systematic mediastinal node dissection affords the most accurate staging and a long-term survival in some patients when the positive regional nodes are also removed. It is safe and easy to do, adds only 20 to 30 minutes to the surgical procedure, and morbidity is minimal. Our reported survival data have been based on the routine use of mediastinal lymph node dissection in conjunction with pulmonary resection. Techniques of lymph node dissection for both right- and left-sided tumors are described along with a historical background of their evolution.