For the past 20 years, flexible fiberoptic bronchoscopy (FOB) has been shown to be an important procedure in the diagnosis and management of patients in intensive care units (ICU). In adults, FOB is used therapeutically to remove retained secretions and to correct atelectasis not improved by conservative means. In the pediatric population, however, FOB is mainly used to diagnose tracheal disease in critically ill children. The principal risks of FOB are hypoxemia and dysrhythmias; hemor rhage and pneumothorax may occur as a result of biopsy procedures. In competent hands, these adverse compli cations of FOB are minimal. Although rigid bronchos copy remains pivotal in most pediatric bronchoscopic procedures, massive hemoptysis, foreign body removal, and laser therapy for occluding tumors of the upper airway, flexible FOB has an increasingly important role in the diagnosis and management of these disorders.