Objectives: to declare the role of Carotid intima-media thickness (CIMT) as a predictor of the severity of Coronary artery disease (CAD) comparing with Syntax (SX) score in patients undergoing coronary angiography. Methods: The present study includes 200 patients (100 patients were diabetics and 100 were not known to be diabetics), diagnosed as patients with CAD, outpatient or admitted in Al-Azhar university Assiut hospital and sohag cardiac specialized centre were included in the study. Demographic characteristics, risk factor profile, laboratory test results, electrocardiographic and echocardiographic findings and coronary angiography findings were assessed. Results: A total of 200 patients were registered for the study. The mean±SD age of the study population was [58.61±9.12] years. Fifty two of patients were females (26%) and one hundred and forty eight were males (74%). 50% of our study group were diabetics, 58% were hypertensives, 39% were smokers, 15% were ex-smokers, 45.5% had dyslipidemia, 46% were obese, 20.5% had positive family history. 43% had STEMI, 27% were UA and 30% were NSTEMI. 71.5% had multi-vessel affected and 28.5% had single vessel affected. Regarding the type of affected vessel 13% was LMT, 81% was LAD, 44.5% was LCX, 58.5% was RCA, 21% was D and 17.5% was OM. The patients were divided into two groups, diabetic group and control group. The mean CIMT was significantly higher in diabetic group than control group (0.980±0.300) (0.883±0.287) respectively with P value <0.020. The mean SX score was significantly higher in diabetic group than non-diabetics (24.495±17.010) (19.275±13.730) with P value <0.018. Conclusion: There is a significant correlation between CIMT and SX score in patients undergoing coronary angiography because of suspected CAD. Therefore, CIMT may not only be associated with CAD extent and severity but also with its complexity.