Identification of asymptomatic patients with diabetes mellitus (DM) at increased risk for coronary artery disease (CAD) remains a challenge. Carotid intima-media thickness (CIMT) has been proposed as a surrogate marker for CAD but only limited data are available. The purpose of the study was to evaluate the potential of CIMT for prediction of CAD in asymptomatic patients with DM. Prospectively, CIMT of the left and right common carotid arteries was assessed by B-mode ultrasound in 150 asymptomatic diabetic patients (50 +/- 13 years old, 83 men). In addition, noninvasive multislice computed tomographic coronary angiography was performed to relate CIMT to the presence and severity of CAD. For this purpose, patients were classified as having (1) no atherosclerosis, (2) nonobstructive atherosclerosis, or (3) obstructive stenosis with >or=50% luminal diameter narrowing. Mean CIMT increased significantly from 0.58 +/- 0.08 mm in patients with normal coronary arteries (n = 59, 39%) to 0.67 +/- 0.12 mm in patients with nonobstructive atherosclerosis (n = 54, 36%). Highest mean CIMT (0.75 +/- 0.12 mm) was observed in patients with obstructive stenosis (n = 36, 25%, p <0.01). Receiver operating characteristics curve analysis yielded a sensitivity and specificity of 85% and 72%, respectively, with a CIMT cut-off value of 0.67 mm, for predicting obstructive coronary atherosclerosis. Multivariate analysis of baseline risk factors showed CIMT to be an independent predictor of any and obstructive atherosclerosis (p <0.01). In conclusion, a significant relation was shown between CIMT and the presence and severity of CAD in asymptomatic patients with DM. Assessment of CIMT may be useful to identify diabetic patients at higher risk for CAD.