Regulator of G-protein signaling 2 (RGS2) is a key molecule in signal pathways of vasoactive peptides, such as angiotensin II and endothelin 1, and is believed to have an important role in the pathophysiology of atherosclerosis. We have previously reported that common polymorphisms of RGS2 are associated with hypertension in Japanese. In this study, we studied whether the three previously identified common polymorphisms of RGS2 (-638A>G, 1026T>A and 1891-1892delTC) could be implicated in carotid atherosclerosis in Japanese patients with hypertension (459 men and 382 woman) and in a Japanese general population (814 men and 956 woman). We assessed two criteria for carotid atherosclerosis: maximal intima-media thickness (M-IMT) and mean-IMT. When subjects with atherosclerotic lesions were defined as having mean-IMT≥1.0 mm, multivariate logistic regression analysis performed after adjusting for confounding factors showed a significant association of the three common polymorphisms, -638A>G (AA versus AG+GG: odds ratio (OR), 1.55; 95% confidence interval (CI), 1.105-2.185; P=0.0113 only for the general population), 1026T>A (TT versus TA+AA: OR, 1.42; 95% CI, 1.027-1.972; P=0.034 for hypertensive subjects and OR, 1.56; 95% CI, 1.129-2.151; P=0.0071 for the general population), and 1891-1892delTC (II versus ID+DD: OR, 1.44; 95% CI, 1.043-2.008; P=0.028 for hypertensive subjects, OR, 1.32; 95% CI 1.002-1.742; P=0.048 for the total general population and OR 1.59; 95% CI 1.155-2.207; P=0.0047 for the general population), with carotid atherosclerosis. When atherosclerosis was defined as M-IMT 1.0 mm, the values of M-IMT were also significantly different between the three genotypes in the three common polymorphisms. Taken together, these data suggest that genetic polymorphisms in RGS2 are associated with intima-media thickening of carotid artery in humans.