The evaluation of children with airway obstruction always involves a history and physical examination. The definitive diagnosis is most often made with microlaryngoscopy and bronchoscopy (MLB), and in cases of extrinsic compression, information is gained from magnetic resonance imaging. Although plain radiographs of the airway are often used as a primary diagnostic modality in children with airway obstruction, the accuracy of plain radiographs in predicting specific airway abnormalities has not previously been evaluated. This study was designed to correlate the findings of plain airway radiographs with the diagnosis made at the time of MLB. Medical records from 1991 to 1996 were reviewed to identify patients that had MLB and airway radiographs within 2 days of one another. One hundred forty-four cases were identified and divided into diagnostic categories. Statistical analysis showed a high sensitivity (>86%) for the accuracy of the radiologic diagnoses of exudative tracheitis, airway foreign body, and innominate artery compression. Laryngomalacia and tracheomalacia had a much lower sensitivity (5% and 62%, respectively). We believe that plain radiographic evaluation of the airway provides important information to the diagnostician. However, plain radiographs can be inaccurate and must be considered along with a history, physical examination, and clinical suspicion. Microlaryngoscopy and bronchoscopy remains the ultimate diagnostic test for airway disorders.