We report a case of an 85-year-old female, previously demented and dependent on others, who presented to the emergency department with sudden dyspnea following a coughing paroxysm. She was polypneic and with a diminished vesicular murmur at pulmonary auscultation but with audible bowel sounds in the right hemithorax. Arterial blood gases showed hypoxemic respiratory failure but the additional blood work was unremarkable. A thoracic radiograph suggested the presence of small bowel on the thoracic cavity. A thoracic computed tomography confirmed the diagnosis of an anterior right giant paracardiac transdiaphragmatic hernia of small bowel through the foramen of Morgagni with secondary passive pulmonary atelectasis. A posterior left transhiatal gastric hernia was also found. She was treated conservatively with nasogastric intubation and discharged home two days later, asymptomatic and without respiratory failure. Spontaneous diaphragmatic hernias are extremely rare, non-traumatic surgical emergencies, almost invariably requiring surgical correction. This case shows that a conservative approach is an alternative in selected patients.