Over a 4-year period we performed 420 endoscopic investigations in 262 patients (aged 1 day-26 yrs) under sedation and local anesthesia, using several different flexible instruments; repeat procedures were performed in 58 children. The most common indications for diagnostic endoscopy were tracheostomy evaluation (27.1%), non-specific chest x-ray changes (13.8%), stridor (12.4%), atelectasis (7.9%), and the sampling of airway secretions or cells by bronchoalveolar lavage (5.5%); indications for 17 therapeutic endoscopies (4%) included the removal of airway secretions and mucus plugs, and aid in difficult intubations. Bronchomalacia (46X), tracheomalacia (41X), obstructing granulation tissue (36X), and laryngomalacia (35X) were the most common diagnoses; in addition, subglottic stenosis was found in 13, a subglottic hemangioma in 5, vocal cord paralysis in 5 and an endobronchial foreign body in 5 children. Findings were normal in 39 (9.3%) cases. A relevant diagnosis was established on 73.7% of all investigations. The diagnostic yield was highest in patients with stridor, persistent wheezing, atelectasis, non-specific chest x-ray changes, and in patients with a tracheostomy. The success rate of therapeutic procedures was 70.6%. Minor complications occurred in altogether 4.3% of cases; all were completely and rapidly reversible. Flexible fiberoptic bronchoscopy is a safe and valuable diagnostic and therapeutic tool for the management of infants and children with respiratory problems.