Background. Mounier-Kuhn syndrome or tracheobronchomegaly is a rare disorder characterized by marked dilatation of the trachea and main bronchi, bronchiectasis, and recurrent respiratory tract infections. Its clinical presentation may vary and mimick a variety of disorders. Case report. A 43-year-old female patient, non smoker, complained of intermittent mild dyspnea. Lung function tests and cardiologic findings were within normal limits. The diagnosis was established by computed tomography, which was undertaken due to recurrent lower respiratory tract infections suggestive of bronchiectasis. The transversal tracheal diameter was 2.8 cm that was the criteria for making the diagnosis. In this sporadic case, no association with other disease or condition known to cause secondary tracheobronchomegaly was established. Conclusion. Although rare in clinical practice, Mounier-Kuhn syndrome is an important differential diagnosis in cardio-pulmonary medicine due to a variety of its clinical manifestations. Nowadays, it is easy to diagnose it owing to advanced imaging techniques.