We report the case of a 6-month-old child who developed acute pulmonary edema because of laryngeal spasm during orthopedic manipulations for congenital hip dysplasia. Laryngospasm was probably secondary to an unsuspected light level of anesthesia, maintained via face mask. No other predisposing factors, such as enlarged adenoid tonsils, laryngitis, epiglottitis, mechanical stimulation of the larynx or aspiration of foreign material were identified. Serious oxygen desaturation and bradycardia ensued, during inefficient attempts at positive pressure ventilation. After emergency intubation without muscle relaxant, copious pink secretions emerged from the airway. Negative pressure pulmonary edema was confirmed by chest X-ray, and short-lasting arterial desaturation despite positive pressure ventilation with high oxygen concentration. This type of pulmonary edema is caused by marked elevated negative intra-airway pressure, massive sympathetic discharge causing a blood shift from the systemic to the pulmonary circulation, and accentuation of physiological ventricular interdependence during forceful inspiratory effort against a closed glottis. As usual in such cases, pulmonary edema and laryngospasm resolved spontaneously without specific treatment, and extubation was carried out uneventfully two hours later. The child suffered no sequelae.