The aim of this study was to evaluate the relationship between aortic intima-media thickness (aIMT) and coronary artery disease (CAD) severity in patients with non-ST-segment elevation myocardial infarction (NSTEMI). SYNTAX score (SS) was calculated. Patients were categorized into 2 main groups according to the SS: patient with high risk (SS >= 13) and low risk (SS < 13). Common carotid artery IMT (cIMT), common femoral artery IMT, and aIMT were measured with a high-resolution ultrasound Doppler system. We had 147 (52.9%) patients in the high-risk group and 132 patients in the low-risk group. Both cIMT and aIMT were significantly increased, and left ventricular ejection fraction (LVEF) was significantly lower in the high-risk group; aIMT (odds ratio [OR]: 1.272, P < .001), cIMT (OR: 1.239, P = .009), and LVEF (OR: 0.931, P = .002) were determined as independent predictors for the high-risk group. When the cutoff value was accepted as 1.25 mm for the aIMT, patients with high SS identification had 74.1% sensitivity and 89.4% specificity (area under the curve: 0.764, P < .001). In conclusion, aIMT detected by abdominal B-mode ultrasonography is closely associated with CAD severity in patients with NSTEMI.