Myocardial infarction complicated by bacterial infection is rare. The present case is an instance in which the infecting organism, Listeria monocytogenes, is also rare—an instance not previously reported. The clinical findings were fever without localized infection, severe atherosclerotic heart disease, a myocardial infarct of indeterminate age, and a left ventricular aneurysm. Additional electrocardiographic findings include left bundle branch block, intraventricular conduction defect, and multiple episodes of ventricular tachycardia, all of which may be associated with myocardial infarction and none of which is specific for suppurative myocarditis. Myocardial enzyme abnormalities were absent. Listeria monocytogenes was identified from blood cultures on the day following the patient's death. This case illustrates the difficulty in diagnosing suppurative myocarditis complicating myocardial infarction and the dire consequence of such infection. A review of the literature is included.