Purpose: To evaluate the ocular circulation in diabetic patients with coronary artery disease (CAD). Methods: Thirty diabetic patients with diabetic retinopathy of grade 20 or 35, as evaluated by the Early Treatment Diabetic Retinopathy Study, were studied. They were divided into those without CAD (15 cases) and those with CAD (over 75% stenosis of carotid artery; 15 cases). All underwent standard ophthalmic examinations and orbital color Doppler imaging. Fifteen healthy controls underwent the same examinations. Results: The peak systolic velocity in the central retinal artery was significantly lower in the two diabetic groups. The end-diastolic velocity in the central retinal artery was significantly lower only in the diabetic patients with CAD. There were no significant intergroup differences in blood flow velocities in the ophthalmic artery, short posterior ciliary artery, and central retinal vein. The blood flow waves were flattened in the diastolic phase for all orbital arteries in significantly more eyes in the diabetic patients with CAD. Echocardiography, performed only in the diabetic patients with CAD, showed that 10 cases (67% ) had reduced systolic functions and/or diastolic functions and/or asynergy of the left ventricle. Conclusions: A decrease in blood flow velocities in the diastolic phase was found in diabetic patients with CAD. The findings indicate that this is probably related to the decrease in cardiac output. Methods: To evaluate the ocular circulation in diabetic patients with coronary artery disease (CAD). Methods: Thirty diabetic patients with diabetic retinopathy of grade 20 or 35, as evaluated by the Early Treatment of Diabetic Retinopathy Study, were studied. They were divided into those Fifteen healthy controls underwent the same examinations. Fifteen healthy controls underwent the same examinations. Results: The peak systolic velocity in the The end-diastolic velocity in the two diabetic groups was significantly lower only in the diabetic patients with CAD. There were no significant intergroup differences in blood flow velocities in the ophthalmic artery, short posterior ciliary artery, and central retinal vein. The blood flow waves were flattened in the diastolic phase for all orbital arteries i had significantly reduced eyes in the diabetic patients with CAD. Echocardiography, performed only in the diabetic patients with CAD, showed that 10 cases (67%) had reduced systolic functions and / or diastolic functions and / or asynergy of the left ventricle. Conclusions: A decrease in blood flow velocities in the diastolic phase was found in diabetic patients with CAD. The findings indicate that this is probably probably related to the decrease in cardiac output.