Recurrent acute myocardial infarction (AMI) is a disastrous condition with high in-hospital morbidity and mortality. However, the relation between location of previous myocardial infarction (MI) and in-hospital outcome in repeat-AMI patients undergoing primary percutaneous coronary intervention (PCI) remains unclear. Using the AMI-Kyoto Multi-Center Risk Study database, clinical background, angiographic findings, results of primary PCI, and in-hospital prognosis were retrospectively compared between primary PCI-treated AMI patients with previous anterior MI (anterior group, n=151) and those with previous non-anterior MI (non-anterior group, n=157). Clinical backgrounds, angiographic findings, results of primary PCI, and in-hospital outcome did not differ significantly between the two groups. On multivariate analysis, Killip class > or =3 at admission, number of diseased vessels > or =2 or diseased left main trunk at initial coronary angiography, and age were the independent predictors of in-hospital mortality in the recurrent-AMI patients, but not the anterior location of previous MI. These results suggest that among recurrent-AMI patients undergoing primary PCI, in-hospital prognosis mostly depends on the severity of acute heart failure at the onset and the residual myocardial ischemia rather than previous MI sites.