The aim of this study was to investigate prevalences of hyperuricemia and the metabolic syndrome (MS) in the Hangzhou population, and the relationship between serum uric acid and the MS. A cross-sectional study was conducted among 4155 subjects (2614 men and 1541 women) aged 20-80 years, recruited through a health check program in Hangzhou, China. Biochemical and haematological parameters were measured by standard methods. The diagnosis of the MS is made when three or four of the following criteria are met: 1) body mess index (BMI) >or= 25; 2) systolic blood pressure >or= 140 mmHg or diastolic blood pressure >or= 90 mmHg; 3) fasting triacyglycerol >or= 1.7 mmol/L (150 mg/dL), high density lipoprotein cholesterol (HDL-C) < 0.9 mmol/L (35 mg/dL) in men and <1.0 mmol/L (39 mg/dL) in women; 4) fasting glucose >or= 6.1 mmol/L (109 mg/dL). Hyperuricemia is defined by cut-off values of > 420 mumol/L for men and > 360 mumol/L for women. Prevalences were 16.9% (N=702) for hyperuricemia and 8.4% (N=349) for the MS. Serum uric acid concentration was significantly higher in males than in females (p<0.0001), and significantly higher in subjects with obesity, dyslipidemia and hypertension compared with those without. In the partial correlation analysis, after controlling for gender, age and creatinine, serum uric acid concentration was significantly positively correlated with BMI (r=0.301, p<0.0001), systolic blood pressure (r=0.151, p<0.0001), diastolic blood pressure (r=0.168, p<0.0001), total cholesterol (r=0.144, p<0.0001) and triacyglycerol (r=0.234, p<0.0001). Results suggest that increased serum uric acid concentration is associated with an increased prevalence of metabolic disorders such as obesity, dyslipidemia and hypertension in the Hangzhou population.