Background : Matrix metalloproteinase-3(MMP3) is known to be involved in protein degradation and co-localized with calcium and fibrin deposits in atherosclerotic lesions indicating a possible role of MMP3 in coronary artery calcification. The aim of this study was to assess the association of plasma level or functional polymorphism of MMP3 and coronary artery calcification Methods and Results : Seventy eight blood samples for MMP3 genotype (A5/A5, A5/A6, A6/A6) determination and for measurement of serum concentration of MMP3 were collected from patients undergoing coronary angiography. The severity of coronary artery calcification was measured from the image of coronary multidetector computed tomography using NIH ImageJ program and expressed as calcium fraction. The subjects of 5A/5A genotype had a tendency to have higher coronary calcium fraction than those of 5A/6A or 6A6A genotype although it was not significant ( 2.60 짹 1.65 vs 1.34 짹 1.63 , 0.89 짹 0.92 p=0.089 ). Serum MMP3 levels were positively correlated with coronary artery calcium fraction (p = 0.035, y=0.055x+0.1253, R2= 0.1944 ). Conclusion : MMP3 5A/5A genotype of high promotor activity is presumed to be associated with a larger area of coronary calcification than 5A/6A or 6A/6A genotype with low promotor activity. These data suggest that proposed effect of MMP3 in the process of coronary calcification might be modified by the MMP3 genotypes.