During the last 12 years, 30 cases of tracheopathia chondro-osteoplastica have been diagnosed at the Department of Otolaryngology of Kuopio University. Ten of these were accidentally revealed by bronchoscopy, 2 by autopsy, but 18 were revealed through a systematic examination. Ten of these 18 were preliminarily diagnosed by indirect laryngoscopy. The average age for women was 51 and for men 42, the youngest patient being 11 and the oldest 71 years of age. The characteristic symptoms were long-term recurrent cough, hoarseness and periodic expectoration. The sputum was frequently abundant and crusty, and sometimes contained streaks of blood. Shortness of breath was a common symptom, but there were often entirely asymptomatic periods. The disease begins with a persistent purulent tracheitis, which, probably owing to calciphylaxis, causes accumulation of calcium salts in the tracheal mucosa. Cartilage and bone later develop around these accumulations. In most of the cases of tracheopathia chondro-osteoplastica in the present series, the condition was associated with atrophic rhinitis or pharyngitis. As the nasal disease improves, some regression may occur, though hardly healing. Calcium and phosphorus metabolism was not disturbed, and no immunological aberrations were found in any of the patients in this series.