Pneumopericardium and pneumomediastinum caused by retrosternal gastric tube ulcer after esophagoplasty is rare. A 73-year-old man who had received retrosternal esophageal reconstruction with gastric tube presented to the emergency department with chest pain and dyspnea. Chest radiography revealed pneumomediastinum, and chest computed tomography (CT) revealed conditions of pneumopericardium and pneumomediastinum. Emergency surgery including removal of retrosternal gastric tube, duodenostomy, partial pericardiectomy and tube thoracostomy was performed to repair the lesion and prevent life threatening complications. Perforation of a peptic ulcer from the retrosternal gastric tube into the pericardium was found during surgery and the diagnosis was proved by pathology. The patient recovered uneventfully.