Broncholithiasis is defined as a cor9ition in which a concretion is present within a bronchus or a cavity in the lung communicating with a bronchus. The usual causes of broncholithiasis are known as tuberculosis, histoplasmosis, silicosis, aspirated calculi, and a few fungal infections. It is generally accepted that the constant motion created by respiration and beating of the heart may cause the peribronchial calcified lymph node to erode into the tracheobronchial tree and to form broncholith. After the analysis of our 6 cases of broncholithiasis which were treated surgically in the Department of Thoracic Surgery, Seoul National University Hospital from 1960 to December, 1985, we could suggest that intrinsic formation of calculi should be regarded as the pathogenesis of broncholithiasis in addition to the extrinsic formation of calculi.