Myxoma is a common benign cardiac tumor that may rarely cause an acute myocardial infarction. A 77-year-old woman was admitted to our hospital with chest pain. Electrocardiography showed an ST elevation in leads V3-6. Transthoracic echocardiography revealed an ovoid mass with fragmentation in the left atrium and hypokinesia of the left ventricular apex. Coronary angiography indicated the presence of a coronary embolism that was suspected to be from the left atrial mass. The mass was removed by emergency surgical resection to avoid a further systemic embolism and was diagnosed pathologically as a myxoma. The patient was discharged after 13 days with no complications.