Magnetic resonance (MR) imaging of the trachea was performed in twenty-one children with congenital or acquired narrowing of the trachea or main bronchi. The demonstration of the trachea and the surrounding tissue and vessels on MR images permitted the evaluation of the cause of trachea, compression and the degree and location of collapse. MRI is a well-suited modality for characterizing tracheal narrowing without employing ionizing irradiation or intravenous contrast medium. In the cases presented MRI should be the diagnostic step of choice after tracheo-bronchoscopy. It is an enrichment of the diagnostic possibilities for extrinsic tracheal or bronchial stenosis in pediatric patients.