Klebsiellarhinoscleroma is a chronic granulomatous disorder of the upper respiratory tract caused by infection with the gram-negative bacillusKlebsiella rhinoscleromatis. Most commonly seen in eastern Europe, Africa, the Middle East, southeast Asia and Central America, this pathogen usually affects the nasopharynx, where chronic infection may go undiagnosed for many years. Diagnosis is often difficult because chronic inflammation causes tissue fibrosis and scarring; clinically, infection may be confused with atrophic rhinitis. Lower respiratory tract involvement is less frequent, but should be suspected when cough, dyspnea, wheezing, or hemoptysis suggest tracheobronchial obstruction. Indeed, the persistent, often indolent course of infection clinically mimics asthma, tracheal stenosis, and endobronchial spread of neoplasm.Klebsiellarhinoscleroma should be considered along with other inflammatory causes of tracheal stenosis such as Wegener's granulomatosis, tuberculosis, sarcoidosis, and fungal infections, especially in immigrants from areas of endemicity. Palliation of airway stenosis, appropriate antibiotic therapy, and close, longterm observation are the keys to successful treatment.