Our purpose was to determine and compare the diagnostic accuracy of flow-mediated dilatation (FMD) and intima-media thickness (IMT). Included were 543 patients. FMD was performed in 543 patients, IMT in 233, and coronary arteriography (CAG) in 442. Analyzing ROC (receiver operating characteristic) curves, FMD </=5.64% showed 89% sensitivity, 62% specificity, 65% positive predictive value (PPV), and 88% negative predictive value (NPV) for the presence of angiographically significant coronary artery disease (CAD). IMT >/=0.788 mm had 71% sensitivity, 62% specificity, PPV 60%, and NPV 73% for the presence of advanced coronary atherosclerosis. FMD >8% or IMT <0.614 mm distinguished a group of patients with a low probability of advanced CAD (95% sensitivity for both and 91% and 81% NPV for FMD and IMT, respectively), whereas FMD </=0% or IMT >/=1.09 mm indicated a high probability for significant coronary stenosis (specificity 95% and NPV 71 and 67%, respectively). FMD and IMT have a clinically applicable diagnostic accuracy for the presence of angiographically significant CAD with a better performance for FMD. FMD and IMT values help us define zones with high and low probability for the presence of advanced coronary atherosclerosis.