Carotid intima-media thickness (IMT), a measure of atherosclerosis, is modulated by multiple risk factors. Accordingly, comprehensive control of risk factors is indispensable for management of atherosclerosis. In this study, as a posthoc analysis of the JART Study we planned two analyses. In the main analysis, we evaluated the effect of intensive lipid-lowering therapy with rosuvastatin on carotid IMT in high-risk patients. We also evaluated efficacy in the presence or absence of each risk factor using the full analysis population in the JART Study. Patients with low-density lipoprotein cholesterol (LDL-C) ≥ 140 mg/dL and max-IMT ≥ 1.1 mm were randomized to rosuvastatin or pravastatin therapy for 12 months. Dosages were allowed to increase to 10 mg/day and 20 mg/day to achieve LDL-goals (aggressive goals for rosuvastatin group and guideline goals for pravastatin group). For the main analysis, we assessed 200 high-risk patients (105 in the rosuvastatin group), as category III or secondary prevention according to the Japan Atherosclerosis Society guideline 2007, whereas we assessed 289 patients in the other analysis. Rosuvastatin significantly slowed the percentage change in mean-IMT at 12 months compared with pravastatin (1.40 ± 10.03% versus 6.43 ± 13.77%, P = 0.005). LDL-C was reduced by 48.1% in the rosuvastatin group and 27.9% in the pravastatin group. The rate of achieving the LDL-C goal was significantly greater in the rosuvastatin group compared with the pravastatin group (P < 0.001). Rosuvastatin slowed the change in mean-IMT in the presence of every risk factor. Thus, intensive lipid-lowering therapy reduced progression of carotid IMT in high-risk patients.