Aims: The effects of statins on insulin resistance and new onset of diabetes are not obvious. The purpose of this study is to evaluate the effects of rosuvastatin on insulin resistance and adiponectin in patients with mild to moderate hypertension. Methods and Results : In a randomized, prospective, single-blind, placebo-controlled study, 53 hypertensive patients were randomly assigned to either control group (n=26) or rosuvastatin 20 mg (n=27) once daily group during a 8-week treatment period. Both group showed significant improvement on systolic blood pressure and flow-mediated dilation (FMD) after 8 weeks treatment. Rosuvastatin treatment showed improvement in total cholesterol, LDL cholesterol, triglyceride levels. Rosuvastatin reduced hs-C reactive protein from baseline but, these were not significant (p = 0.68). Control and rosuvastatin treatment did not significantly change HbA1C levels from baseline (mean change: 0.2% vs. -3.46%, p = 0.20), fasting insulin levels (mean change: -15.63% vs. 2.74%, p = 0.58), and glucose levels (mean change: -6.16% vs. -2.38%, p = 0.60). And, control and rosuvastatin treatment did not significantly change QUICKI insulin sensitivity index (mean change: 2.63% vs. 3.02%, p = 0.88). Plasma adiponectin level significantly increased in rosuvastatin group (p=0.046) but showed no significant difference compared to control group (mean change: 23.18% vs. 23.13%, p = 0.16). Conclusion: The study showed that 8 weeks of rosuvastatin 20mg therapy show no significant improvement or deterioration on fasting glucose, insulin resistance, and adiponectin level.