This study evaluated the association between progressively higher levels of fasting glycemia (G) and insulin resistance parameters with coronary artery disease (CAD) in patients referred for coronary angiography. All 145 patients (age 58.4+/-0.9 years, 51.7% men) underwent clinical and laboratory evaluation before coronary angiography and subjects were divided into four groups: normal (N, <88 mg/dl), high-normal (H-N, 89-99 mg/dl), impaired fasting glucose (IFG, 100-125 mg/dl) and diabetes (DM, >126 mg/dl or known diabetics). Arteriographic evidence of CAD was determined by two criteria: (1) a 30% or greater diameter stenosis in at least one major coronary artery; (2) a 70% or greater diameter stenosis in at least one major coronary artery. HOMA-IR increased progressively according to each group: N=1.74+/-0.2, H-N=3.14+/-0.3, IFG=4.67+/-0.6 and DM=8.00+/-2.9; p=0.001. The proportion of patients with CAD according to both criteria increased with each G level: CAD criteria 1: N=39.4%, H-N=50%, IFG=60% and DM=69.6%, p=0.006; CAD criteria 2: N=27.3%, H-N=30%, IFG=36% and DM=50%, p=0.03. We demonstrated a significant association between subtle disturbances of the glucose metabolism, assessed by subnormal levels of fasting glucose and insulin resistance parameters, and angiographically documented coronary artery disease.