BACKGROUND: Five year survival rate of postoperative stage I non-small lung cancer(NSCLC) reaches to 66%. In the remaining one third of patients, however, cancer recurs and overall survival of NSCLC remains dismal. To evaluate clinical and pathologic characteristics of recurred NSCLC, we studied patterns and factors for postoperative recurrence in patients with staged I, II NSCLC. METHOD: A retrospective analysis was performed in 234 patients who underwent radical resection for pathologic stage I, II NSCLC. All patients followed for at least one year were included in this study. RESULTS: 1) There were 177 men and 57 women. The median age was 63. The median duration of follow up was 732 days (range 365~1,695 days). The overall recurrence rate was 26.5% and the recurrence occurred at 358.8 +/- 239.8 days after operation. 2) The age of recurred NSCLC patients were higher (63.2 +/- 8.8 years) than that of non-recurred patients (60.3 +/- 9.8 years)(p=0.043). The recurrence rate was higher in stage II (46.9%) than in stage I (18.8%, p<0.001) NSCLC. The size of primary lung mass was larger in recurred (5.45 +/- 3.22 cm) than that of non-recurred NSCLC (3.74 +/- 1.75 cm, p<0.001). Interestingly, there were no recurrent cases when the resected primary tumors were less than 2cm. 3) Distant recurrence was more frequent than locoregional recurrence (66.1% vs. 33.9%). Distant recurrence rate was more frequent in female and adenocarcinoma. Brain metastasis was more frequent in patients with adenocarcinoma than squamous cell carcinoma (p=0.024). CONCLUSION: The tumor size and stage were two important factors for recurrence. Considering that distant brain metastasis was more frequent in patients with adenocarinoma, prospective study should follow to evaluate the effectiveness of preoperative brain imaging.