Abstract: AIM: To investigate the effects of telmisartan on insulin resistance and serum retinol-binding protein 4 in patients with essential hypertension. METHODS: Forty-five subjects with essential hypertension were treated with telmisartan (80 mg/day) or losartan (100 mg/day) combined with long-acting calcium antagonist, if necessary, for 16 weeks. Waist and hip circumference, body mass index, blood pressure, fasting plasma glucose (FPG), insulin (FPI), lipid and retinol-binding protein 4 (RBP4) were measured before and after the treatment. Insulin sensitivity was estimated by homeostasis model assessment (HOMA-IR). RESULTS: Compared with baseline levels, systolic and diastolic blood pressure decreased significantly in both groups. But the levels of HOMA-IR and RBP4 decreased significantly only in telmisartan group. CONCLUSION: Telmisartan improves insulin resistance and decreases serum RBP4 level in patients with essential hypertension.