A tracheal diverticulum, probably of congenital origin, was discovered accidentally during the course of a broncho-pulmonary affection. Diverticuli of the trachea are usually found during a simple systematic radiological examination, or when an established pulmonary condition is being investigated. Routine bronchography, alone, or associated with a tomograph, can be used to demonstrate its characteristics and precise location. Bronchoscopy may then be carried out in order to study the area surrounding the diverticular orifice more closely, and to establish the condition of its mucous lining. Several evolutive stages are involved in the pathogenesis of tracheal diverticuli, varying from a rudimentary bronchiole to megalotrachea, which, for many authors, is an autonomous condition because of its anatomical and pathological make-up, producing its own well-defined symptomatology.