Background and objectives : Pentraxins 3 (PTX3) known as a long pentraxin is highly expressed in the heart, wherease, C reactive protein(CRP) is a short pentraxin and is produced from the liver. In previous studies, PTX3 was increased in acute phase of myocardial infarction(MI) and showed prognostic significance in MI patients. The aim of this study was to estimate the value of PTX3 as an inflammatory maker in patients with Metabolic Syndrome(MS) defined by the National Cholesterol Education Program. Subjectives and Methods : Total 59 subjects (mean age: 60짹12 years, M:F = 36:24) were enrolled and they were divided into MS group(N=32, mean age:62짹 12years, M: F=19:12) and control group(N=28, mean age:59짹11 years, M:F=16:12) according to the parameters of NCEP. Intima media thickness(IMT) of common carotid artery was measured using high frequency transducer. Serum PTX3 and CRP concentration was measured with ELISA. Results : 1. No significant correlation was observed between serum PTX3 and CRP concentrations(r= -0.117, p=0.396). 2. The serum PTX3 concentration was significantly increased in MS than control group(1.18짹1.0 vs 0.73짹0.3 ng/ml, p=0.028). 3. The serum CRP level was not significantly different between MS and control group (2.15짹2.0 vs 1.25짹1.3 ug/ml, p=0.055). 4. Among the parameters determining MS, increasing waist circumference was independently associated with supramedian PTX3 concentration(p<0.01, odds ratio(95% confidence interval) : 5.96(1.58-22.5)). 5. Right and Left mean IMT was increased in MS than control group(0.94짹0.20 vs 0.81짹0.20, p<0.05, 0.93짹0.20 vs 0.79짹0.20 mm, p<0.05). 6. There was no correlation between serum PTX3 concentration and IMT. Conclusions : PTX3 can be an useful inflammatory marker in metabolic syndrome and central obesity is independent factor for increment of serum PTX3 level.