Background: Metabolic syndrome (MS) is regarded as an important risk factor for coronary artery disease (CAD). According to NCEP criteria, MS could be divided into 16 independent subgroups by combining 5 criteria. The aim of this study is to identify the subgroups with the highest potential for CAD in non-diabetic MS. Methods: The study population included 2510 subjects (mean age 55 짹 10.5) consisting of 728 angiographically documented CAD patients,560 patients with hypertension and 1305 healthy subjects. Data collection included investigation of CAD risk factors, BP and anthrometric measurements. Blood samples were analyzed for serum lipid profiles, FBS, apoA1, apoB, and insulin. Insulin sensitivity was calculated according to the formula of the homeostasis model assessment (HOMA index). Results: Among 2510, 707 (28.2%) met the Asian-modified NCEP criteria. Because the number of patients was minimal in subgroups with impaired fasting glucose (IFG), they were merged into one group for statistical analyses. Finally, 6 subgroups of MS were defined and multivariate adjusted odds ratio for CAD was calculated (Table 1). Conclusion: The MS comprise of several heterogeneous groups. The risk for CAD seems to be somewhat higher in subgroups that have common features of abdominal obesity and low HDL in non-diabetic MS patients. This work was supported by a grant of Ministry of Health and Welfare, Republic of Korea (00-PJ6-PG5-23-0001)