There is growing evidence of the presence and relevance of coronary microvascular abnormalities in many cardiac diseases. In particular, it has been recently shown that dilated cardiomyopathy (DCM) is characterized by dysfunction of the coronary microvessels since its very early onset. Coronary microcirculatory dysfunction is not an effect of myocardial damage but seems in turn to cause progressive contractile impairment, ventricular dilation and heart failure. The mechanisms of the progressive deterioration of cardiac function in DCM are largely unknown but both myocardial hypoperfusion and myocardial ischemia at the microvascular level are most probably involved. It has been demonstrated that the presence and the extent of coronary microcirculatory dysfunction in patients with early stage DCM is an independent and relevant predictor of worse prognosis. From these studies it is more and more evident that the coronary microcirculation is involved in the pathogenesis ofDCMand should be considered a new target of treatment in those cardiac diseases at risk to evolve towards heart failure.