Background: Angiotensin II receptor blockers (ARBs) are known to be superior in improving vascular structural and functional indices and metabolic parameters among blood pressure (BP) lowering drugs. Although there are important structural differences among the various molecules within the same ARB class of drugs, there are few clinical comparative studies with different ARBs regarding both vascular and metabolic effects. The aim of this study is to compare those effects between telmisartan and valsartan. Methods: Sixty hypertensive patients who either had no history of antihypertensive treatment or had received no antihypertensive drugs for over 4 weeks were randomized to receive either telmisartan (80mg/day; n=30) or valsartan (160mg/day; n=30) for 12 weeks. We measured anthropometric data, lipid and glucose metabolism parameters, vascular indices and echocardiographic data at baseline and study end. Results: Both group showed significant reductions in systolic and diastolic BP after treatment and the changes were not significantly different between two groups. Compared with those receiving valsartan, patients in the telmisartan group achieved significant reductions in carotid-femoral pulse wave velocity (cfPWV; -7.6%, p=0.023) and left ventricular mass index (LVMI; -9.6%, p=0.018) and showed trends for reduction in total cholesterol (-5.7%, p=0.075) and triglyceride (-13.7%, p=0.058). There were no significant changes in other vascular and metabolic parameters in both groups. When we compared, however, the changes between two groups, there was only significant difference in LVMI (p=0.036). Conclusions: Although the level of BP reduction was similar in two groups, compared with valsartan, telmisartan significantly improved LVMI and the result might be based on the beneficial effect of telmisartan on cfPWV. There were no significant changes in both group regarding metabolic parameters. Our results need to be confirmed by larger clinical study.