• Impacted subglottic foreign bodies may produce upper airway obstruction and clinical signs simulating croup or asthma. We identified the roentgenologic and clinical features in six patients. In four of these patients, the parent had not observed the aspiration episode, so that the diagnosis was delayed. Roentgenologic studies demonstrated subglottic narrowing of the upper airway with a homogeneous, poorly defined radiodensity within the narrowed segment. These roentgenologic studies are usually diagnostic; therefore, if infants or young children present with stridor of undetermined cause, soft-tissue upper airway roentgenography is indicated.