BACKGROUND : Arterial stiffness has been recognized as a significant predictor of cardiovascular event, while experimental data indicates that angiotensin II-type I receptor blocker (ARB) treatment reduces arterial stiffness. Telmisartan is highly selective angiotensin II-type I receptor blocker (ARB) with PPAR gamma activation. The purpose of present study is to assess the effect of telmisartan treatment on arterial stiffness in metabolic syndrome patients. METHODS: The influence of telmisartan (80mg daily for 8 weeks) on arterial stiffness was determined in 25 metabolic syndrome patients (60.5 years, 20 male) using a single-blind, prospective protocol. Arterial stiffness [brachial-ankle pulse wave velocity (PWVba), carotid-femoral pulse wave velocity (PWVcf)] were measured at drug-free baseline and after 8-week of telmisartan monotherapy. RESULTS: Routine laboratory exam has not shown abnormal finding after treatment. Mean body mass index was 25.3 gm/m2. HDL (48짹9 vs 50짹11 mg/dL, p<0.01) hsCRP (0.7짹0.9 vs 0.5짹0.5 mg/L), HbA1C (6.8 vs 6.0 %), and NT-proBNP (113짹69 vs 89짹43 pg/mL) were improved after treatment but, not statistically significant. Systolic BP (151짹15 vs 132짹18 mmHg, p <0.01) and diastolic BP (90짹14 vs 82짹10 mmHg, p=0.025) were significanly decreased. All arterial function indices were improved after telmisartan therapy (PWVba: from 1647짹197 to 1506짹177 cm/sec, p<0.01, PWVhf: from 1091짹172 to 1007짹156 cm/sec, p<0.01 and PWVhc: from 998짹 203 to 923짹206 cm/sec, p<0.01). Multivarate regression analysis revealed that PWVba change was independent of systolic BP change (p<0.05). CONCLUSION : Telmisratan treatment may affect favorably arterial stiffness in metabolic syndrome patients.