BACKGROUND: This study was performed to investigate the difference in high sensitivity C-reactive protein (hsCRP) and metabolic syndrome according to the fasting glucose level, especially between the groups of less than 100 mg/dL and 100-109 mg/dL, which were conventionally categorized into normal levels. METHODS: Those who underwent routine medical checkups aged above 20 (male, 3,221; female, 3,334) at a Health Promotion Center (Seoul, Korea) were divided into normal fasting glucose group I (glucose <100 mg/dL), normal fasting glucose group II (glucose, 100-109 mg/dL), impaired fasting glucose group, and diabetes mellitus group. The hsCRP, obesity index, blood pressure, total cholesterol, triglyceride, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C) and lipoprotein(a) [Lp(a)] were compared among the groups. The hsCRP and the components of metabolic syndrome were compared. RESULTS: The hsCRP level, age, obesity index, blood pressure, total cholesterol and triglyceride significantly increased along with the increment in fasting glucose level in the 4 groups. The hsCRP had a positive correlation with the fasting glucose level, age, and systolic blood pressure, while it had a negative correlation with HDL-C. The metabolic syndrome was more common in the group with a higher level of glucose. CONCLUSIONS: The group with glucose level of less than 110 mg/dL, conventionally categorized into normal range, needs to be subdivided into a group of 100-109 mg/dL and a group of less than 100 mg/dL. The former group seems to require more efforts to have the glucose level to be maintained under the level of 100 mg/dL.