Criteria of obesity in the Chinese population with multiple metabolic risk factors remains unclear. The objective was to determine the best anthropometrical measurements with regard to the metabolic syndrome (MetS) and to propose optimal cut-off values. Between April and August, 2007, 3,704 men and 6,392 women aged 18-85 years were recruited from four community centers. Medical examinations included measurement of weight, height, waist circumference (WC), hip circumference, fasting blood triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), glucose concentrations, and blood pressure (BP). Body mass index (BMI), waist to hip ratio (WHR), WC and waist to stature ratio (WSR) were calculated. Four metabolic risk factors were examined: 1) high BP; 2) high levels of TG; 3) low levels of HDL-C; 4) impaired glucose tolerance. The relationships between studied indices and risk factors were analyzed using partial correlation analyses, analysis of variance (ANOVA), linear regression, and Receiver Operator Characteristic (ROC) curve analysis. The optimal cut-off values of each obesity index were calculated using ROC analysis respectively. All obesity indices were positively associated with metabolic risk factors. Area under curve (AUC) of WC was the largest for >or= 2 risk factors after adjustment for age in both genders. Optimal cut-off points for WC were 89 cm in men, and 80.5cm, 82.5cm, and 89.5cm in < 40-yr, 40-60-yr, and > 60-yr women respectively. Waist circumference is best associated with metabolic risk factors among the studied indices in Chinese adults. Indices of abdominal obesity for older age groups tend to be higher than younger age groups in women.