Background: Surgery is the only curative treatment for operable non-small lung cancer (NSCLC) and the importance of adjuvant chemotherapy for stage IB patients is unclear. Herein, we evaluated prognostic factors for survival and factors related with adjuvant treatment decisions for stage I and IIA NSCLC patients without lymph node metastasis. Materials and Methods: We retrospectively analyzed 302 patients who had undergone curative surgery for prognostic factors regarding survival and clinicopathological factors related to adjuvant chemotherapy. Results: Nearly 90% of the patients underwent lobectomy or pneumonectomy with mediastinal lymph node resection. For the others, wedge resection were performed. The patients were diagnosed as stage IA in 35%, IB in 49% and IIA in 17%. Histopathological type (p=0.02), tumor diameter (p=0.01) and stage (p<0.001) were found to be related to adjuvant chemotherapy decisions, while operation type, lypmhovascular invasion (LVI), grade and the presence of recurrence were important factors in predicting overall survival (OS), and operation type, tumor size greater than 4 cm, T stage, LVI, and visceral pleural invasion were related with disease free survival (DFS). Multivariate analysis showed operation type (p<0.001, hazard ratio (HR):1.91) and the presence of recurrence (p<0.001, HR:0.007) were independent prognostic factors for OS, as well visceral pleural invasion (p=0.01, HR:0.57) and LVI (p=0.004, HR:0.57) for DFS. Conclusions: Although adjuvant chemotherapy is standard for early stage lymph node positive NSCLC, it has less clear importance in stage I and IIA patients without lymph node metastasis.