Anomalous origin of the left main coronary artery from the right anterior aortic sinus is a rare condition (0.02 to 0.07%) and its clinical significance is sometimes controversial. The authors present the case of a 44-year-old female with this anomaly and septal course with clinical, electrocardiographic, scintigraphic and cineangiographic evidences of myocardial infarction without coronary lesions. Literature is reviewed regarding diagnosis, clinical significance, pathophysiology and management. It is probably the first evidence of the potential danger of this anomaly with septal course.