Although it is known that patients with polycythemia vera (PV) are at increased risk of myocardial infarction (MI) secondary to thrombosis, ventricular septal rupture in this setting has never been reported. Ventricular septal rupture complicating a small anteroseptal MI is reported in a patient with PV and with only minimal ectasia of the left anterior descending coronary artery. Despite small infarct size these patients may be predisposed to myocardial hemorrhage, increasing the likelihood of myocardial rupture.