Pneumopericardium, defined as the presence of air inside the pericardial cavity, is generally considered to be an emergency because it can cause cardiac tamponade. Pneumopericardium associated with self-expanding metallic stent (SEMS) placement is extremely rare. We present a fatal case of pneumopericardium caused by SEMS placement. An 84 year-old man had tumor-induced stenosis of the jejunal limb after total gastrectomy. SEMSs were inserted twice to improve the symptoms without complications. Two days after the implantation of a central venous access port for anorexia, the patient suddenly complained of chest pain and dyspnea, and decreased blood pressure was observed. Chest CT revealed the presence of air in the pericardial cavity. As urgent echography showed cardiac tamponade, pericardiocentesis was performed immediately. The hemodynamic condition temporarily improved after drainage. Although we planned the placement of an additional SEMS to close the fistula, he died 3 days after the onset of symptoms. Pneumopericardium with cardiac tamponade is a potentially fatal situation. An early diagnosis and treatment are important for the management of esophago-pericardial fistula. Prompt drainage is the best management and SEMS placement can achieve effective short-term results.