Objective To examine insulin resistance and high sensitivity C-reactive protein (hsCRP) association with clinical and angiographic severity of coronary artery disease (CAD) in patients with normal glucose tolerance.Methods In 638 consecutive patients with normal glucose tolerance, 221 had atypical chest pain and normal coronary artery (control group), 279 had stable angina and CAD (SAP group), and 138 suffered acute myocardial infarction (MI group). The degree of CAD was further divided into borderline lesion (lumen diameter narrowing 50%-69%), significant 1-, 2- or 3-vessel disease (luminal diameter narrowing ≥70%). Fasting serum glucose, insulin and hsCRP levels and lipid profiles were measured, and homeostasis model assessment for insulin resistance (HOMA-IR) was calculated. Multivariate analysis was performed to assess risk factors for 3-vessel disease or acute MI.Results Serum hsCRP, lipoprotein (a) levels, and insulin resistance index (IRI) were higher in AMI group than those in SAP and control groups. Serum hsCRP level and IRI were also higher in 3-vessel disease than those in other groups. Multivariate regression analysis revealed that insulin resistance, cigarette smoking, serum hsCRP, and lipoprotein (a) levels were independent risk factors for acute MI. Lipoprotein (a) elevation was an independent risk factor for 3-vessel disease.Conclusion Insulin resistance and high serum hsCRP level were associated with occurrence of acute MI and angiographic severity of coronary disease in patients with normal glucose tolerance.