The heart may be critically damaged by objects of unimpressive size or appearance. We report a case of cardiac tamponade due to penetration of the right ventricle by an acupunture needle. A 59-year-old man was admitted due to dyspnea and chest pain. He had recieved acupuncture therapy during 10 years for chronic right upper abdominal pain. He was diagnosed as cardiac tamponade due to hemopericardium caused by an broken a cupuncture needle detected on fluoroscopy, computerized tomography and trans-esophageal echocardiography, and the needle was successfully removed by cardiac surgery. The patient was discharged uneventfully and followed at the outpatient department.