Background. Hyperuricemia is associated with hypertension, vascular disease and cardiovascular (CV) disease. However, the role of serum uric acid (SUA) level as an independent risk factor for CV and renal morbidity in hypertension remains controversial. Accordingly, we aimed to determine whether SUA levels are independently and specifically associated with coronary flow reserve (CFR) impairment in hypertensive patients. Methods. We examined 80 never treated and newly diagnosed hypertensive individuals. The hypertensive individuals were divided into two groups based on CFR values. Results. Subjects with altered CFR (v2) had significantly higher SUA levels compared with those with normal CFR (>= 2) (346.0 +/- 98.1 vs 260.7 +/- 75.6 mu mo1/1, p<0.0001). After adjusting for potential confounders, including age, sex, body mass index, blood pressure, lipids and creatinine, we found that SUA levels were independently associated with CFR impairment (beta=-20.417, p < 0.0001). We also found that SUA levels were a good predictor of low CFR at the receiver- operating characteristic curve. Area under the curve was 76% (95% CI 0.64 - 0.88), and SUA levels were significantly predictive of low CFR (p < 0.0001). Conclusions. These results support a role for SUA level as an independent marker of target organ damage in hypertension.