A patient with acute severe mitral regurgitation resulting from papillary muscle dysfunction which developed on the third day of acute myocardial infarction underwent early successful mitral valve prosthetic replacement with concomitant aortocoronary saphenous vein bypass. The concept of acute severe mitral regurgitation due to an infarcted papillary muscle which has not actually ruptured and an aggressive approach to such a catastrophic event early in the course of acute myocardial infarction are emphasized. The risk is well worth the gratifying result obtained in our patient who successfully underwent such a combined operative procedure for one of the early complications of acute myocardial infarction.