OBJECTIVE: Comparison of investigations of the airway in ventilator-dependent infants. DESIGN: Consecutive infants with suspected upper airway abnormalities were investigated using rigid bronchoscopy and tracheobronchography. SETTING: Tertiary pediatric and neonatal intensive care units. PATIENTS: Eight infants with suspected airway abnormalities. INTERVENTIONS: Rigid bronchoscopy and tracheobronchography. MEASUREMENTS AND MAIN RESULTS: Structural abnormalities, segmental narrowing of the airways and the effect of various levels of positive-end expiratory pressures on the narrowings were documented. In six of the eight cases, additional airway abnormalities were diagnosed with tracheobronchography compared with rigid bronchoscopy. CONCLUSIONS: In cases of suspected abnormalities of the upper airway in small infants unable to be weaned from ventilatory support, tracheobronchography may be a more reliable investigation method than rigid bronchoscopy. The ability to assess the structural and dynamic components of the airway accurately and safely allows a correct and long-term treatment plan to be established in this group of patients.