In patients with acute myocardial infarction (AMI), little is known about the correlation between prognostic variables and aspects of ruptured plaque at the coronary angiography. Five hundred patients with acute myocardial infarction were studied in a consecutive and prospective manner; of these, 264 patients were excluded mainly because of the presence of an occluded culprit coronary artery. The remaining 236 patients were divided according to the presence (113, 52%) or absence (126, 48%) of angiographic aspects suggestive of ruptured plaque, and correlated with 49 clinical, electrocardiographic, in-hospital complications, procedures, and other angiographic prognostic variables. The variables that correlated significantly and independently with angiographic aspects of ruptured plaque were: presence of thrombi and higher degree of residual stenosis at the culprit coronary artery, as well as white ethnic group.