We report a rare case of airway obstruction caused by megaesophagus associated with achalasia. A 78-year-old man was admitted with post meal dyspnea, decreased consciousness, expiratory and inspiratory wheezing, and respiratory distress. Arterial blood gas analysis showed findings of marked acute respiratory acidosis (pH 7.18, PaCO2 75 mmHg, PaO2 225 mm Hg, HCO3- 22 mmol/L). An emergency laryngoscopy was performed because of a suspected airway obstruction, but no abnormalities were observed from the airway to the glottis. Noninvasive positive pressure ventilation (NPPV) was immediately introduced, and the respiratory rate and breathing pattern was normalized. A chest X-ray showed an enlarged upper mediastinal outline and an ill-defined border of the trachea. A computed tomography (CT) scan showed an enlarged esophagus with a maximum diameter of 9.90 cm, compressing the trachea to the back of the sternal notch. Following removal of the esophageal contents using a nasogastric tube, NPPV was discontinued with no respiratory episodes. After he was stabilized, he was transferred to another hospital for endoscopic myotomy. In a review of the literature, we identified 66 cases of airway obstruction due to achalasia, mainly in older women. None of the patients received NPPV. As a differential diagnosis for acute airway obstruction, achalasia-related airway obstruction should be considered, particularly in older women. Furthermore, since this condition is suspected to involve tracheomalacia, NPPV may be a useful respiratory support therapy.