Preconditioning of the myocardium with short episodes of sublethal ischemia will delay the onset of necrosis during a subsequent lethal ischemic insult. Ischemic preconditioning seems to involve a variety of stress signals which include activation of membrane receptors and signaling molecules such as protein kinase C, mitogen-activated protein kinases, opening of ATP-sensitive potassium channel, and expression of many protective proteins. The purpose of this review is to assess the current position in this field and to facilitate future research.