Uric acid (UA) is independently associated with the emergence of hypertension. Nocturnal nondipping pattern of hypertension is associated with a greater risk of cardiovascular, renal, and cerebrovascular complications than dippers. The aim of the present study was to evaluate the relationship between the circadian blood pressure rhythm and UA level in patients with newly diagnosed essential hypertension. The study included 112 essential hypertensive patients and 50 healthy controls. The hypertensive patients were divided into two groups according to the results of 24-hour ambulatory blood pressure monitoring, including 60 dippers (35 men, 25 women; mean age, 52.6 +/- 15.8 years) and 52 nondippers (29 men, 23 women; mean age, 55.9 +/- 13.2 years). Nondippers had significantly higher serum UA levels than the dippers and controls (5.8 +/- 0.8, 5.1 +/- 0.9 and 4.2 +/- 0.9 mg/dL, respectively; P<.001). Serum high-sensitivity C-reactive protein levels were also significantly higher in the nondipper group than the other groups (P<.001) and significantly correlated with serum UA (r=0.358, P<.001). Multivariate logistic regression analysis revealed an independent positive association between serum UA levels and nondipper pattern (odds ratio, 2.28; 95% confidence interval, 1.333.94; P=.003). Serum UA is strongly and independently associated with the nondipper circadian pattern in essential hypertension.