1). In 1001 patients with acute myocardial infarction 403 cases were found (40.2%) showing possible relapse. A study was made of 125 cases (12.5%) with positive diagnosis of acute myocardial infarction relapse, and among them, 12 were found to be occurring for the third time. Is possible for the real frequency of the iterative infarction to be even higher, because many cases were dismissed (27.7%) for lacking of conclusive electrocardiographic data pointing to myocardial transmural infarction. 2). Investigations were conducted about the evolutive condition of the danger factors in the coronary profile as well in the male as in the female group. Besides, a comparative study was made about symptoms, complications, morbidity and mortality. Clinical, enzimatic and electrocardiographic proofs were found, in every case, of a new myocardial transmural necrosis which was in evolution, with waves of injury and ischemia. Thirty eight deaths were registered in hospitals (30.4%) and in 25 of these, a necropsic study was conducted. 3). This illness is more frequent among men than among women, in a 3.5 to 1 proportion. The recurrent myocardial necrosis tends to be more frequently present during the first year following the first episode. In women, the first myocardial infarction as well as the iterative infarction occur at an older age than in men. 4). The influence of personality and stress is a very important factor of danger in the iterative infarction. Familiar antecedents of ischemic cardiopathy constitute a danger factor in patients presenting a single episode of myocardial infarction; nevertheless they don't seem to have a determining influence in this group of relapsing infarction. Although this study confirms with statistics that smoking has a decisive influence in the first myocardial infarction, neither frequency nor mortality of the relapsing infarction are in any way modified by the diminishing or suppression of the smoking habit.