Thirty seven flexible bronchoscopies were performed in 33 infants in a neonatal intensive care unit, using a 2.2 mm flexible ultrathin bronchoscope. Twenty eight procedures were performed via an endotracheal tube or tracheostomy and nine in spontaneously breathing infants. Indications for endoscopy included persistent atelectasis and/or emphysema (n = 21), unexplained acute respiratory distress (n = 10), stridor (n = 3), assessment of congenital abnormalities of the tracheobronchial tree (n = 2), and follow up of an endobronchial granuloma during the course of corticosteroid treatment (n = 1). Abnormal airway dynamics and/or abnormal structure were seen in 23 of 37 cases. In 54% of the procedures, the results of bronchoscopy had a direct effect on further management. The procedure was well tolerated and completed in less than two minutes. Our results suggest that the ultrathin flexible bronchoscope improves airway exploration and the understanding of respiratory disorders during the first months of life, particularly in ventilated infants.