Background and Objectives: Intensive lipid-lowering therapy with statins improves the clinical outcomes and patient survival and it reduces the progression of atherosclerosis. Intravascular ultrasound (IVUS) has been used for calculating the plaque volumes to evaluate the mechanisms that may be involved in the progression or regression of coronary artery disease. We used serial IVUS exams to assess the efficacy of rosuvastatin on plaque regression in angina patients who had a mild to moderate degree of vulnerable plaque burden. Subjects and Methods: This study was a prospective, randomized, comparative study for lipid lowering therapy with using rosuvastatin 20 mg or atorvastatin 40 mg. IVUS was performed during the baseline coronary angiography and it was repeated after 12 months of treatment. The efficacy parameters included the changes in the atheroma volume and the lipid pool size as determined by IVUS. A total of 45 lesions in 30 patients were analyzed (rosuvastatin: 24 le