Coronary plaques can be reduced by some medications. The aim of this study was to compare the effects of 2 angiotensin II receptor blockers (olmesartan at 20 mg/day or valsartan at 80 mg/day) on coronary plaque by coronary intravascular ultrasound. One hundred hypertensive patients with stable angina pectoris who underwent elective percutaneous coronary intervention were randomly selected to receive 1 of the 2 angiotensin II receptor blockers after coronary intervention. Nontarget coronary lesions with mild to moderate stenosis were measured by volumetric intravascular ultrasound at baseline and after 6 months. After 6 months, both the olmesartan and the valsartan groups showed significant reduction of the examined coronary plaque volume (46.2 ± 24.1 mm³ at baseline vs 41.6 ± 21.1 mm³ at 6 months: 4.7% decrease, p = 0.0002; and 47.2 ± 32.7 mm³ at baseline vs 42.5 ± 30.2 mm³ at 6 months: 4.8% decrease, p = 0.002, respectively). There was no statistically significant difference of plaque regression between the 2 groups (p = 0.96). In conclusion, there was a significant decrease from baseline in the coronary plaque volume in patients with stable angina pectoris who received olmesartan or valsartan for 6 months. In addition, there was no significant difference in the reduction of plaque volume achieved by these 2 medications.