It has been shown that repeated brief coronary occlusions increase myocardial resistance towards prolonged episodes of ischemia. This phenomenon, which renders the heart more tolerant to ischemia with subsequent limitation of infarct size, has been termed ischemic preconditioning. Ischemic preconditioning also protects the heart against postinfarction left ventricular dysfunction and ventricular arrhythmias. Ischemia induced activation of adenosine receptors, and opening of ATP-sensitive potassium channels and stress protein synthesis are thought to be the potential mechanisms of this phenomenon. The exploration of the exact mechanisms of ischemic preconditioning might improve the treatment strategies for acute myocardial infarction in the future.