Background: Differential diagnosis between ischemic (IDCM) and the non-ischemic cardiomyopathy (NIDCM) constitutes a challenge in the daily medical practice. Coronary artery disease (CAD) is a major cause of heart failure associated with left ventricular systolic dysfunction (LVSD). The prognosis of LVSD is significantly influenced by the etiology of heart failure and therefore differentiation of significant CAD from other etiologies is important. Carotid intima-media thickness (IMT), carotid plaque and carotid stenosis >50% are useful predictors for cardiovascular events, including CAD and stroke. Objectives: To assess the usefulness of carotid ultrasonography in differentiating between ischemic and non-ischemic dilated cardiomyopathy. Methods: We retrospectively studied 75 subjects with dilated cardiomyopathy (DCMP) of uncertain origin who underwent echocardiography and coronary angiography between February 1, 2021, and august 30, 2022. They have been applied for carotid ultrasonography. Results: Carotid atherosclerosis was found to be very common in ischemic and rare in non-ischemic cardiomyopathy. CAD was found in 47 patients (62.6%, IDCM group) on coronary angiography. Carotid IMT> 1.0% (85.1% vs 21.4%, p<0,001) was significantly higher in the IDCM group. Carotid plaque (63.8% vs 3.6%, p<0.001) was significantly higher in the IDCM group and Carotid stenosis > 50% (27.7% vs 0.0%, p<0.001) was also, higher in the IDCM group. Conclusion: Carotid intima-media thickness (IMT), carotid plaque and carotid stenosis > 50% are useful predictors for IDCM in DCMP of unknown origin.