Background: Diabetes is a major factor for the development of coronary artery disease. Atherosclerosis is thought to arise as a result of a chronic inflammatory process within the arterial wall. Insulin resistance is central to the pathogenesis of type 2 diabetes and may contribute to atherosclerosis, either directly or though associated risk factors. Rosiglitazone, a peroxisome proliferator-activated receptor gamma agonist, is used in the treatment of type 2 diabetes mellitus, and previous data suggest that it may hay anti-inflammatory effects on atherosclerosis. The study was performed to evaluate the effect of rosiglitazone on arterial stiffness. Methods: This study consisted of 30 type 2 diabetic patients. These subjects were classified into the two groups medicated by glimepiride (amaryl group, n=15, 62짹6 years, M:F=5:10) and glimepiride and rosiglitazone (avandia group, n=15, 65짹9 years, M:F=1:14). In each group, 0 and 6 months of medical treatment periods plasma hs-CRP, lipid profile, and HbA1c were measured. At the same time we measured the pulse wave velocity using an automatic device (PP 1000). Results: Plasma hs-CRP level was decreased in the avandia group compared with amryl groups significantly. The C-F and C-R PWV of the avandia group have improved significantly as compared with the amaryl group. Conclusion: These findings suggest that the rosiglitazone improves the arterial stiffness in type 2 diabetic patients.