Interrelationship between C-reactive protein (CRP) and metabolic syndrome (MS) was evaluated in a community-based cohort of 9773 Koreans aged 40-69 years. Metabolic syndrome was defined by criteria of the National Cholesterol Education Program. CRP was measured by validated high-sensitivity assay. The median CRP level was 1.4 mg/1, and significantly increased as the number of components of MS increased (P trend <0.001). CRP levels were significantly but marginally correlated with waist circumference (r=0.18), triglyceride (r=0.14), blood pressure (r=0.11), HDL-cholesterol (r=-0.10), and fasting glucose (r=0.09) (all P values<0.01). Odds ratios of the highest quartile of CRP for each component of MS; i.e., waist circumference, triglyceride, glucose metabolism, blood pressure, and HDL-cholesterol were 2.36, 1.79, 1.70, 1.32 and 1.28, respectively. The highest quartile of CRP was independently associated with 1.72-fold increased risk of MS in our logistic regression model adjusted for age, sex, BMI, and smoking. This study demonstrated that CRP is a strong associating factor of MS in Korean population. We recommend further evaluation of CRP levels in the other Asian ethnic groups to establish biological plausibility as the risk factor for MS in all ethnic groups.