The hiatus hernia and sigmoid volvulus are usually found in older patients. The delay of the treatment of both of these illnesses may result in increased morbidity and mortality. We report a case of an isolated intrathoracic hiatal herniation of the twisted sigmoid colon. The patient complained about cramping abdominal pain, vomiting, and dyspnea. Chest X-ray and CT scan of the thorax showed a distended colonic segment in the posterior mediastinum. The patient underwent cruroplasty, Nissen fundoplication, and sigmoid colon resection. This is the first report of such a rare case.