The last decades, coronary microcirculation has become a very important territory because of its role in coronary circulation physiology and pathophysiology. Only its implication in coronary artery disease was known at the beginning, but subsequently its role in many others diseases was shown. The nontraditional pathophysiological construct sustains that myocardial microcirculatory dysfunction is the primary event, and the atherosclerotic plaque rupture or erosion is the secondary event. In some instances, the coronary microvascular dysfunction may be an epiphenomena, an important marker of risk or even a cause, thus becoming therapeutic target.