Large clinical trials have elucidated that lipid-lowering therapy using statins reduces cardiovascular events in patients with coronary artery disease (CAD). The benefit of statin therapy is proportional to the achieved low-density lipoprotein cholesterol level (LDL-C) up to 70 mg/dl. On the basis of this evidence, the American Heart Association and American College of Cardiology offer an optimal LDL-C goal of <70 mg/dl for patients with a very high risk of CAD. In addition, with regard to acute coronary syndrome (ACS), which has a high risk for future cardiac events because of the presence of vulnerable plaque, intensive lipid-lowering therapy from the early stage is the standard treatment. On the other hand, the mechanism of inhibition of cardiac events by statins is thought to be predominantly based on stabilization of plaque, but research on the role of plaque regression is also advancing. The clinical significance of intensive lipid-lowering therapy using statins will be discussed from the following standpoints: (1) large-scale clinical trials around the world; (2) the relationship with plaque regression and stabilization; (3) the relationship with the diverse effects of statins; and (4) evidence generated from Japanese patients.  (Circ J 2010; 74: 1718 - 1730)