BACKGROUND: Cardiovascular risk factors have been divided into 2 categories, modifiable risk factors, and nonmodifiable risk factors. Clustering of risk factors may increase the risk of CAD more than any of the factors alone and often related to each other. We conducted this study to examine clustering of modifiable risk factors, to analyse associated factors with the clustering of metabolic risk factors, and to evaluate the risk of CAD according to the number of cardiovascular risk factors. METHODS: The case series comprised of 166 patients with angiographically confirmed coronal artery disease, who were admitted to the Division of Cardiology of a Medical Center in Seoul. The controls were 137 persons composed of patients with normal coronary arteriogram or patients with normal myocardial SPECT for chest pain. We surveyed their life style habits, measured anthropometric variables, and analyzed biochemical markers among CAD patients and controls. RESULTS: Modifiable risk factors, smoking, hypertension, diabetes, hyperchesterolemia, and low HDL-C were clustering each others among middle-aged Korean. Clustering of metabolic risk factors, hypertension diabetes, hyperchesterolemia, and low HDL-C were associated with white-collar griup, low physucal activity, non-exercise, high BMI(body mass index) and high WHR(waist-hip ratio). The odds ratios for CAD in men with 3,4 more than 5 risk factors were 2.0(95% Cl : 0.9-4.5), 2.9(95% Cl : 1.2-6.7), and 12.2(95% Cl 3.5-42.0) respectively, compared with men with less than 2risk factors. The corresponding odds ratios in women were 3.4(95% Cl : 1.3-9.0),71(95% Cl : 1.2-13.5), and 4.5(95% Cl : 1.0-21.5) respectively. CONCLUSION: These findings show that modifiable cardiovascular risk factors cluster among middle-aged Korean. The more the cardivascular risk factors, the higher the CAD risk in men and not only for clustering cardiovascular risk factors but also for CAD risk.