The authors analyse in a retrospective study a group of 31 patients with explorative thoracotomy, which was performed on account of inoperable bronchogenic carcinoma. The causes of inoperability were assessed and the period of survival after explorative thoracotomy was evaluated. From the total number of 496 patients indicated in 1985-1990 for surgery on account of bronchogenic carcinoma 465 pulmonary resections were made and 31 (6.25%) explorative thoracotomies. In all these patients the c TNM and p TNM classification was assessed. Disagreement in the evaluation of these parameters was found in particular in parameter T which was in agreement only in three instances. Conversely agreement was more frequent in parameter cN and pN (n = 18). The most frequent cause of inoperability was penetration of the tumour into the mediastinum (n = 25). Death within 30 days after surgery was not recorded in the group, three patients of 31 survived 5 years after exploration. Explorative thoracotomy did not exert a negative effect on the period of survival which corresponded to the given stage of the disease. Due to improving preoperative examination methods the number of explorative thoracotomies will probably decline in future, but at present it cannot be completely eliminated.