Serum uric acid has been positively associated with incident hypertension, but previous studies have had limited ability to explore this relationship across sex and ethnic strata. We sought to evaluate this association in a biethnic cohort of middle-aged men and women. Participants in the Atherosclerosis Risk in Communities (ARIC) study who were free of hypertension at baseline (N=9104) were evaluated for hypertension at 3-year intervals over 4 examinations. Adjusted Cox proportional hazards models evaluated risk of incident hypertension or progression of blood category for each SD higher baseline serum uric acid. At baseline, the mean age was 53.3 years (range: 45 to 64 years), with a mean (SD) systolic blood pressure of 113.8 (12.2) mm Hg, mean diastolic blood pressure of 70.2 (8.6) mm Hg, and mean serum uric acid of 5.7 (1.4). Higher serum uric acid was associated with greater risk of hypertension in the overall cohort (hazard ratio for each SD of higher uric acid [95% CI]: 1.10 [1.04 to 1.15]) and in subgroup analyses (black men: 1.32 [1.14 to 1.54]; black women: 1.16 [1.03 to 1.31]; white men: 1.01 [0.94 to 1.09]; white women: 1.04 [0.96 to 1.11]), after adjustment for age, baseline blood pressure, body mass index, renal function, diabetes, and smoking. The pattern was similar when modeling blood pressure progression (overall: 1.10 [1.05 to 1.14]; black men: 1.26 [1.11 to 1.42]; black women: 1.18 [1.06 to 1.31]; white men: 1.05 [0.99 to 1.11]; white women: 1.05 [1.00 to 1.12]). In conclusion, serum uric acid was positively associated with incident hypertension over 9 years of follow-up, and this relationship was stronger in blacks than in whites. More research is warranted concerning the physiological and clinical consequences of hyperuricemia, especially in blacks.