The postoperative 5-year survival rate is about 50-85% in the patient with the stage I non-small-cell lung cancer (NSCLC). It is remains unclear how we should give these patients adjuvant radiotherapy and chemotherapy after operation. We performed a postspective study to assess the prognostic and treatment guiding significance of lymph nodes micrometastasis (LMM) in patients with completely resected NSCLC at stage I.