The instable angina pectoris belongs to the prodromes of an acute transmural my ocardial infarction, to which we refer every fresh angina pectoris, increase and prolongation of the anginous pain after stress and the appearance of pain in rest. Retrospectively we established the instable angina pectoris in 45% of the cases of a transmural myocardial infarction. Prospectively the syndrome of the instable angina pectoris was followed by a transmural myocardial infarction in 18%. In 14% of the cases with instable angina pectoris without provable transmural myocardial infarction a sudden heart death took place. In the discussion the author deals with questions of the not clarifyed pathogenesis and therapy. The instable angina pectoris is, indeed, an important clinical syndrome, but from the point of view of the short-time prognosis in our opinion it has not the presumed significance for the development of the transmural myocardial infarction and the sudden heart death.