Silent myocardial ischemia seems a relatively frequent manifestation of coronary insufficiency. The practice of more and more sophisticated tests to detect myocardial ischemia shows that it is a relatively frequent pathological occurrence. It occurs in patients with an abnormality or a transient or constant failure of the alarm system, represented by pain during the ischemia. It is an heterogenous picture which may take the appearance of a completely silent ischemia (the metabolic, hemodynamic and electrical consequences of ischemia being the only symptoms of coronary insufficiency, demonstrated by the presence of severe, angiographic or anatomical, stenoses); of a silent transient ischemia (with alternance of symptomatic and silent episodes or with silent episodes after myocardial infarction); of myocardial necroses without pain or ischemic myocardiopathies. It is the consequences of either an ischemia which is too moderate to reach the pain threshold, or a severe ischemia in patients presenting alterations of the transmission system and of the perception of pain. It has metabolic, hemodynamic and anatomical consequences which may lead to necrosis or degeneration and fibrosis of the myocardium. The prognosis of a painless disease is difficult to make but it does not seem to be as poor as the one of the usual forms of ischemic cardiopathies. Medical treatment is mandatory, and surveillance of its efficacy must be systematic using the techniques of detection of the ischemia.