INTRODUCTION: Serum uric acid (UA) has been known to have a positive association with blood pressure (BP). However, the relationship between serum UA and BP in different age groups is unclear. METHODS: A total of 45,098 Koreans who underwent health examinations at Korea Association of Health Promotion with no history of taking drugs related with UA and/or BP were analyzed for determining the relationship between serum UA and BP. RESULTS: In men <40, serum UA was significantly associated with systolic (beta = 0.25, p = 0.002) and diastolic BP (beta = 0.41, p < 0.001) after adjustment for age, diabetes, dyslipidemia, body mass index, and estimated glomerular filtration rate. Men between ages 40 and 59 showed similar results regarding diastolic BP. The association between serum UA and BP was stronger in women <40 (beta = 0.54, p < 0.001 for systolic BP; beta = 0.65, p < 0.001 for diastolic BP) and in between 40 and 59 (beta = 0.51, p < 0.001 for diastolic BP). The association was not significant in men and women > or =60. The odds ratios (ORs) of hyperuricemia for hypertension were 1.25 (95% confidence interval [CI], 1.08 to 1.45; p = 0.003) and 1.33 (95% CI, 1.11 to 1.60; p = 0.002) in men <40 and in between 40 and 59, respectively, in the multivariate analysis. The OR was 2.60 (95% CI, 1.37 to 4.94; p = 0.0034) in women <40. The relationship between hyperuricemia and hypertension was not significant in other age/gender groups. DISCUSSION: In contrast to the elderly of 60 and over, the non-elderly showed significant associations between serum UA and BP.