Respiratory distress from upper airway obstruction is an unusual but potentially catastrophic emergency in young children. It may be caused by a number of different processes, alone or in combination, including an acute infectious process, a congenital anomaly, or a foreign body in the airway or esophagus. A working knowledge of the anomalies and diseases of the upper airway is of primary importance in pediatric emergency medicine. Classification of airway pathology can be based on the anatomic location, the patient's age, the urgency of the symptoms, and whether it is a congenital or acquired lesion or an infectious or noninfectious process. The starting point for any classification is an appreciation of the unique aspects of pediatric airway anatomy.