Background and Objectives: In previous studies, Pentraxin 3 (PTX3) can be a useful inflammatory marker in the metabolic syndrome and central obesity is an independent factor for an increment of the serum PTX3 level. The aim of this study was to estimate the value of PTX3 as an inflammatory maker in patients with metabolic syndrome (MS) after ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Subjects and Methods: Dec 2007 and Jun 2008, 73 subjects (mean age: 60짹12 years, M:F=62:11) with STEMI underwent primary PCI were enrolled. We estimated the waist circumference, waist/hip ratio, body mass index (BMI), visceral/total fat volume via FAT-computed tomography (CT) in the central obecity and compared with the serum PTX3 concentrations. Results: The serum PTX3 concentration was closely related to visceral fat volume(r=.374, p=.032) and visceral/fat volume ratio(r=.344, p=.050) on FAT-CT, respectively. The serum PTX3 concentration was not related to waist circumference (r=.015,p=.96), waist circumference/hip ratio (r=.194,p=.38) and BMI (r=-.016,p=.129), respectively. Among the parameters determining the MS, an increasing visceral fat volume was the most associated with the supramedian PTX3 concentration (p <.213, odds ratio: 1.048, 95% confidence interval: 0.974–1.128). Conclusions: PTX3 can be a useful inflammatory marker in patients with MS after STEMI undergoing primary PCI and visceral fat volume via FAT-CT is the most reliable factor for an increment of the serum PTX3 level.