We evaluated the effect of levothyroxine in subclinical hypothyroidism (SCH) on arterial stiffness, lipid profile and inflammation. Thirty-four patients with SCH were included. Patients were treated with levothyroxine for 7 months. Arterial stiffness was evaluated by Augmentation index (AIx). After accomplishing euthyroidism, the AIx decreased from 8.3±17.2 to 6.5±14.3(P<0.01) and AIx percentage decreased from36.2 11.5 ± to 9.1±33.2 (P =0.03). Systolic blood pressure decreased from 20±134.7 to mmHg 13.7±127.6 (P<0.01). No significant improvement was found in other parameters. In patients whose AIx's decreased, LDL-cholesterol levels decreased by 37.1±-15.5 mg/dl compared to the patients whose AIx's didn't decrease and LDL-cholesterol increased by 57.4±24.1 mg/dl (P=0.057). We concluded that in patients suffering from SCH, treatment with levothyroxine had a significant beneficial effect on arterial stiffness and systolic blood pressure and no effect on lipid profile or inflammation.