Tracheal diverticulum is a rare entity. When it does occur, it is usually discovered incidentally in an asymptomatic patient as an outpouching from the tracheal wall, usually on the right side. It can be either congenital or acquired. A tracheal diverticulum may act as a reservoir for secretions that may spill over into the tracheobronchial tree, predisposing affected patients to cough, dyspnea, stridor, and chronic chest infection. The author describes 4 cases of tracheal diverticulum—3 congenital and 1 acquired—that were discovered on chest x-ray. The congenital form was found incidentally in 3 asymptomatic middle-aged women, and the acquired case (a tracheobronchial diverticulum) was discovered during a workup for chronic cough and fever in a young man. All 4 patients were thoroughly evaluated with conventional chest and neck radiographs, barium-swallow imaging, linear tomography, computed tomography, and magnetic resonance imaging. Resection of these tracheal diverticula was not considered for any patient. The author also reviews the literature on tracheal diverticulum.