The aim of the study was to analyze the effect of cigarette smoking on the occurrence of sarcoidosis. Sixty patients were examined (17 smokers had 43 nonsmokers). A control group consisted of 60 healthy subjects (33 smokers and 27 nonsmokers). The study showed sarcoidosis to more frequently occur in nonsmokers. Apart from the confirmation that sarcoidosis is predominantly a disease of nonsmokers, our aim was to determine whether smoking has an effect on the extent, course and outcome of the disease. Thus, at the beginning of the study the following examinations were performed in patients with sarcoidosis: chest X-ray, functional respiratory tests, determination of arterial blood acid-base status, blood cells, elastase and C-reactive protein in serum, and the cellular component of the bronchoalveolar lavage. Chest X-ray, functional respiratory tests and acid-base component of arterial blood were repeated after one year. In our patients, hilopulmonary sarcoidosis was most frequent (66.7%). No significant difference was found between smokers and nonsmokers according to radiographic extent of the disease. Analysis of the cellular component of the bronchoalveolar lavage showed significantly more macrophages and less lymphocytes in smokers. Analysis of serum indicators showed no differences between smokers and nonsmokers. Smokers and nonsmokers did not differ according to values of forced expiratory volume in the first second (FEV1). However significantly more nonsmokers had mild degrees of decreased FEV1 (75%-60%) at the beginning of the study, and significantly more smokers had a higher degree of respiratory pathway obstruction (60%-45% and less), both at the beginning and end of the study. At the beginning of the study, significantly higher values of residual volume (RV) and total lung capacity (TLC) were recorded in smokers. No statistically significant difference was found between smokers nad nonsmokers according to the extent of the disease, frequency of extrathoracic localization of disease and use of corticosteroids. Comparison of radiographic finding at the end of the study showed no significant difference between smokers and nonsmokers. There was no difference according to outcome, depending on the therapy used. Based on the results of this study the authors conclude that smoking plays a certain protective role in the occurrence of sarcoidosis, although smoking has no effect on the extent, course and outcome of the disease.