Diabetic retinopathy (DR) is an early and frequent marker of other vascular complications of diabetes and its relation with coronary ischemia is known. The aim of the present study was to evaluate the association between DR and indices of coronary artery disease (CAD) severity and extent determined by coronary angiography. Sixty-nine diabetic patients undergoing coronary angiography for suspected CAD were evaluated. The severity and extent of CAD were scored from coronary angiograms by using 3 scores. Retinopathy was graded by fundus examination. There were differences in the severity score, extent score, number of vessels with disease, duration of diabetes, diabetes therapy, history of previous myocardial infarction (MI), and serum creatinine level among patients with and without DR. CAD severity was associated with the presence of DR (r: 0.53, P < 0.001), grade of DR (r: 0.52, P < 0.001), duration of diabetes (r: 0.28, P: 0.019), history of previous MI (r: 0.36, P: 0.002); and serum creatinine level (r: 0.24, P: 0.049) where the presence of DR was the only independent factor related to the severity score in multivariate analysis (r: 0.48, P < 0.001). The parameters related to the extent score were the presence of DR (r: 0.50, P < 0.001); grade of DR (r: 0.48, P < 0.001); previous MI (r: 0.37, P: 0.002) and age of the patient (r: 0.26, P: 0.033). Factors independently related to the extent score in multivariate analysis were the presence of DR (r: 0.37, P: 0.001), previous MI (r: 0.30, P: 0.006), and age of the patient (r: 0.22, P: 0.003). Among diabetics who are suspected of having CAD, those with retinopathy have more diffuse and severe coronary atherosclerosis, compared with diabetics without retinopathy. This cannot be explained by a longer duration or inferior control of the disease.