Recent reports have suggested that ergonovine stress echocardiography is a safe and accurate procedure for the diagnosis of coronary vasospasm. We experienced a case of heart arrest caused by ergonovine stress echocardiography. A 44 year-old female patient was referred to our emergency room for evaluation of chest pain. She had been admitted to another hospital complaining of chest pain and syncope. The finding of a coronary angiogram was normal and an ergonovine stress echocardiography was performed in order to diagnose the coronary vasospasm, which may be an etiologic mechanism in an unstable angina. After 250 microgram of ergonovine was administered intravenously, we suspected segmental wall motion abnormality (hypokinesia of the inferior wall). An additional dose (100 microgram) was administered to confirm the diagnosis. The patient complained of severe chest pain and dizziness. Segmental wall motion abnormalities progressed and heart arrest finally developed. She recovered following cardiopulmonary resuscitation and was discharged without complication.