The effectiveness of lymph node dissection in the treatment of non-small cell lung cancer is evaluated. The extent of lymphadenectomy in the treatment of NSCLC is still controversial. Although some centers perform only mediastinal lymph node sampling with resection of suspicious lymph nodes, others recommend radical, systematic mediastinal lymph node dissection to improve survival and achieve a better staging. Reports of the literature on the subject are reviewed and the results achieved with the various procedures are analyzed. A personal technique to perform mediastinal lymph node dissection is described.