Increased coagulation activity may be involved in the pathogenesis of atherosclerosis and in the localized occlusive thrombus formation. Rrecently, several genetic variations of genes in coagulation and fibrinolytic system have been identified. The purpose of this study was evaluated the role of genetic variations in the prothrombin and factor V gene for CAD in Korean. 106 male patients with CAD and 132 male healthy controls were participated in this study. Among the study subjects 77 patients who were not taking anticoagulant drugs and 95 controls were analyzed for prothrombin and factor V coagulant activity. The genotype was determined by SNP-IT method. The genetic variation for prothrombin G2210A and factor V Leiden was not detected in our standard sample subjects(n=52). The allele frequencies of the prothrombin 165M(exon3) and factor V 485K(exon 10) were 0.57, 0.62, respectively. There were no significant differences in the genotype frequencies of prothrombin T165M between control and CAD groups. However, in individuals with unfavorable lipid profiles( total cholesterol >= 200mg/dl) showed significantly increased risk for CAD(adjusted odds ratio 5.04, 95% CI 1.71-14.8, p=0.003). Mean prothrombin activity in 165T carrier group was significant lower than that of in 165MM group in both control and CAD group (control : 105 짹 15 vs 117짹21%, p<0.05. CAD : 107짹19 vs 114짹15%, p<0.05). The frequency of the RR genotype of the factor V R485K polymorphism was significantly higher in control than in the patients group( 18% vs 8%, p<0.05). In the multivariate logistic model as covariate with age, waist, hypertension, plasma levels of total choleterol, triglyceride, insulin resistance index, smoking and drinking, the 485K allele was as an independent risk factor for CAD(OR 3.14, 95% CI 1.10-8.96, p<0.05). Prothrombin 165MM genotype was linked with elevated levels of prothrombin activity and in subjects with unfavorable lipid profiles, the prothrombin T165M gene variation was as an independent risk factor for CAD. Factor V R485K polymorphism was not related with factor V activity but associated with increased risk of CAD in Korean.