BACKGROUND: Surgical resection is the only way to cure non-small cell lung cancer(NSCLC) and the prognosis of NSCLC in patients who undergo a complete resection is largely influenced by the pathologic stage. After surgical resection, recurrences in distant sites is more common than local recurrences. An effective postoperative adjuvant therapy which can prevent recurrences is necessary to improve long term survival. Although chemotherapy and radiotherapy are still the mainstay in adjuvant therapy, the benefits of such therapies are still controversial. We initiated this retrospective study to evaluate the effects of adjuvant therapies and analyze the prognostic factors for survival after curative resection. METHODS: From 1990 to 1995, curative resection was performed in 282 NSCLC patients with stage I, II, IIIa, Survival analysis of 282 patients was performed by Kaplan-Meier method. The prognostic factors, affecting survival of patients were analyzed by Cox regression model. RESULTS: Squamous cell carcinoma was present in 166 patients (59%) ; adenocarcinoma in 86 patients(30%) ; adenosquamous carcinoma in 11 patients (3.9%) ; and large cell undifferentiated carcinoma in 19 patients(7.1%). By TNM staging system, 93 patients were in stage I ; 58 patients in stage II ; and 131 patients in stage IIIa. There were 139 postoperative recurrences which include 28 local and 111 distant failures (20.1% vs 79.9%). The five year survival rate was 50.1% in stage I ; 31.3% in stage II ; and 24.1% in stage IIIa(p<0.0001). The median survival duration was 55 months in stage I ; 27 months in stage II ; and 16 months in stage IIIa. Among 131 patients with stage IIIa, the median survival duration was 19 months for 81 patients who received postoperative adjuvant chemotherapy only or chemo-radiotherapy and 14 months for the other 50 patients who received surgery only or surgery with adjuvant radiotherapy (p=0.2982). Among 131 patients with stage IIIa, the median disease free survival duration was 16 months for 21 patients who received postop. adjuvant chemotherapy only and 4 months for 11 patients who received surgery only(p=0.0494). In 131 patients with stage IIIa, 92 cases were in N2 stage. The five year survival rate of the 92 patients with N2 was 25% and their median survival duration was 15 months. The median survival duration in patients with N2 stage was 18 months for those 62 patients who received adjuvant chemotherapy and 14 months for the other 30 patients who did not(p=0.3988). The median survival duration was 16 months for those 66 patients who received irradiation and 14 months for the other 26 patients who did not(p=0.6588). We performed multivariate analysis to identify the factors affecting prognosis after complete surgical resection, using the Cox multiple regression model. Only age(p=0.0093) and the pathologic stage(p <0.0001) were significant prognostic indicators. CONCLUSION: The age and pathologic stage of the NSCLC patients are the significant prognostic factors in our study. Disease free survival duration was prolonged with statistical significance in patients who received postoperative adjuvant chemotherapy but overall survival duration was not affected according to adjuvant therapy after surgical resection.