Abstract: Objective :To evaluate pre-and postoperative mediastinal metastasis and survival rateand to discuss the necessity of systematic mediastinal lymphadenectomy and mediastinal lymph nodesampling during surgery of stage-N₀ non-small cell lung cancer (NSCLC). Methods :Comparative studyof postoperative mediastinal metastasis and survival rate of N₀ NSCLC between those without metastasis(N₀) and with metastasis (N₁ or N₀) was conducted to evaluate the necessity of systematic mediastinallymphadenectomy and mediastinal lymph node sampling during surgery of N₀ NSCLC. Results :The to-tal accuracy of cTNM staging was 42.32 (201/475), and the difference was more significant in thosewithout metastasid:\PDF\.pdfs (pT₁N₀M₀,pT₂N₀M₀) than those with metastasis (pT₁N₁M₀,pT₁N₂M₀,pT₂N₁M₀,pT₂N₂M₀) in the stage-ⅠNSCLC (cT₁N₀M₀,cT₂N₀M₀) (P<0.01), but the difference was not significantbetween cT₃N₀M₀ and pT₃N₁M₀, pT₃N₂M₀. Conclusions :Though no evidence of mediastinal lymphnode metastasis has been found in the stage-Ⅰ NSCLC (cT₁N₀M₀,cT₂N₀M₀), the systematic mediastinallymphadenectomy and mediastinal lymph node sampling in clinical N0 NSCLC operations are still nec-essary owing to the difference between the clinical stage and postoperative pathologic stage. Any localtherapy without systematic mediastinal lymphadenectomy and mediastinal lymph node sampling is in-complete and unsatisfactory in the treatment of stage-N0 NSCLC.