Results of surgical treatment for primary lung cancer patients who underwent noncurative resection from 1979 to 1988 (the latter period) in our department were compared with those treated before 1979 (the former period). Noncurative rate decreased from 39.8% (the former period) to 28.0% (the latter period). The common causes of noncurative resection in the former period was tumor rest in mediastinal lymph nodes (34.0%) and that in chest wall or diaphragma (Ch + Dia; 31.6%) while those of the latter period were intrapulmonary metastasis (p.m.: 21.4%) and tumor rest in the mediastinal lymph nodes. Five year survival rate improved significantly from 5.6% of the former period to 28.6% of the latter period (p less than 0.01, Generalized Wilcoxon test). Compared with the 5 year survival rate of the former groups with pleuritis carcinomatosa, pleural dissemination, p.m. and Ch + Dia, the rate of the latter groups showed significant improvement from 0%, 0%, and 6.25% to 53.3%, 38.6% and 22.1%, respectively.