In the Czech Republic, lung cancer is the most frequent malignant tumor in men. In 1990 the incidence was 99.6/100,000 for men and 15.8/100,000 for women. Neither diagnostic nor therapeutic approaches have changed significantly in the last 10 years. Patients undergoing lung resection have a chance of long-term survival. In this retrospective study, the authors analysed the data of 252 patients undergoing the operation for non-small cell lung cancer (NASCL) in the period 1985-1990. Of all patients who in that period had lung cancer diagnosed in our clinic, only 22% were operated on. Lobectomy was the most frequent type of operation (45%), and exploratory thoracotomy was carried out in 13%. The epidermoid type of cancer was the most frequent one (62%). Comparing cTNM with pTNM, concordant results were found in 55% of the series, 39% were clinically underestimated and 6% overestimated. By the time of the evaluation (31 December 1992), 78% of all patients who had undergone surgery during the study period had died. The most frequent cause of death was lung cancer metastasis. In the subseries of patients who died within 1 month after surgery (10% of all patients), the most frequent cause of death was pneumonia. The survival curve shows the best prognosis for patients in the Ist TNM stage, with 40% surviving 5 years. The authors consider the results of this study to favour aggressive surgical treatment of NSCLC patients.