Angiotensin II receptor blockade has been shown to have a beneficial effect on the angiopathies of hypertension and hyperglycemia in patients with type 2 diabetes. However, the effect of angiotensin II receptor blockade on monocyte and endothelial cell adhesion markers in type 2 diabetes is poorly understood. We investigated the effects of valsartan on these markers in 53 hypertensive patients with and without type 2 diabetes mellitus. Levels of monocyte activation markers (soluble CD14: 2.1+/-0.9 vs. 3.3+/-1.4 microg/ml, p<0.01; monocyte chemotactic peptide: 392+/-94 vs. 489+/-114 pg/ml, p<0.05; and monocyte-derived microparticles: 264+/-98 vs. 511+/-128/microL, p<0.01) and endothelial cell activation markers (soluble E-selectin: 41+/-11 vs. 61+/-20 ng/ml, p<0.001; and soluble vascular cell adhesion molecule-1: 478+/-82 vs. 584+/-101 ng/ml, p<0.01) were significantly increased in hypertensive patients with type 2 diabetes compared to normotensive controls. In addition, the concentrations of adiponectin were significantly decreased in patients with type 2 diabetes (8.1+/-3.1 vs. 5.2+/-2.5 microg/ml, p<0.01). Regardless of the presence of diabetic complications, both systolic and diastolic blood pressures significantly decreased after valsartan administration (valsartan 80 mg/day for 8 weeks). Monocyte and endothelial cell activation markers were decreased significantly in patients with type 2 diabetes after valsartan treatment, but not in non-type 2 diabetic patients. In addition, valsartan alleviated hypoadiponectinemia in hypertensive patients with diabetes (before vs. after: 5.2+/-2.5 vs. 7.6+/-2.7 microg/ml, p<0.001) but did not increase adiponectin levels in the non-diabetic hypertensive group, for which the average adiponectin level was normal prior to treatment. These results suggest angiotensin II receptor blockade (valsartan) may be beneficial as an anti-atherosclerotic therapy in patients with type 2 diabetes in addition to its anti-hypertensive action.