The ventilation function was studied in 103 pulmonary tuberculosis patients of pneumoconiosis-risk occupations in the absence of pneumoconiosis and in 51 patients who were not exposed to dust. Patients of "dust" occupations were found to have a decrease in the parameters of external respiration and bronchoscopic findings more often showed chronic bronchitis. The initial signs of pneumoconiosis were revealed in the histological examination of surgically removed lung segments in 83.4% of the patients.