To assess whether the survival of patients who underwent surgical resections for non-small cell lung cancer (NSCLC) improved, we examined the time trends for survival after operation. A total of 851 consecutive patients with NSCLC who underwent surgical resections between 1979 and 2000 were retrospectively reviewed by 3 groups according to year of the operation: the early period (from 1979 to 1986, n = 138), the middle period (from 1987 to 1993, n = 288), and the late period (from 1994 to 2000, n = 425). There were 606 men and 245 women with a mean age of 65.4 years. The histologic type included 453 adenocarcinoma, 282 squamous cell carcinoma, and 63 large cell carcinoma. The pathologic stage included 203 stage I A, 171 stage I B, 21 stage II A, 117 stage II B, 180 stage III A, 123 stage III B, and 36 stage IV diseases. The mean age at the middle and late periods showed a significant increase compared with the early period. There were no significant histologic differences among the three periods. The ratio of patients with stage I A disease increased significantly at the middle and late periods compared with the early period. The 5-year survival rate of the 851 patients was 43.7%, and the median survival was 44.8 months. The 5-year survival rates at the early, the middle, and the late periods were 33.3%, 44.2%, and 45.8%, respectively, with significant improvement at the middle and late periods compared with the early period. The overall 30-day operative mortality was 2.2% (19/851): 8.7% (12/138) at the early period, 1.4% (4/288) at the middle period, and 0.7% (3/425) at the late period, showing significant decrease during the middle and late periods compared with the early period. The postoperative prognosis of patients with resected NSCLC during the later periods had a better survival, which was caused by an increase in the ratio of patients with stage I A disease, and a decrease in the rates of operative mortality.