Objective　To investigate the prognostic significance of N1 stage in non-small cell lung cancer (NSCLC) by comparing is survival with N0 and N2 stages. Methods　From Jan. 1982 to Dec. 1994, 138 NSCLC patients with surgical-pathological N1 stage had received complete mediastinal lymph node dissection. Two subgroups of N1 node were identified by using New Regional Lymph Node Classification for Lung Cancer Staging. Their prognostic significances were tested and 5-year survival rates were compared with those of surgical-pathological N0 (307 cases) and N2 (176 cases) patients received radical operation during the same period. Results　The overall 5-year suvival rate of N1 patients was 30.4 %. five-year survival was significantly better when N1 involvement was intralobar as compared with extralobar involvement, 50.3 % versus 26.5 % (P=0.001). Intralobar N1 5-year survival was similar to that of N0 (51.4 % vs 50.3 %), and extralobar N1 5-year survival was similar to that of N2 with singl focus (26.5 % vs 23.5 %). Conclusion　N1 stage in NSCLC is a compound with two subgroups; the prognostic significance of intralobar subgroup is related to N0 stage and extralobar subgroup is related to that of single focus N2.