Background: Atherosclerosis is a diffuse process that may affect different vascularbeds with considerable overlap between coronary, cerebrovascular and peripheralarterial disease. These conditions are related to similar predisposing risk factors andgenetic predisposition. Presence of atherosclerosis at one arterial site should promptthe clinician to assess for an involvement, symptomatic or asymptomatic, at otherarterial distributions. Currently, No data is known about the relationship between thethe numerical value of syntax score as an estimate of severity of coronary arterydisease and other vascular beds affection in form of carotid and lower limbs arterialatherosclerotic disease. We aimed to assess the strength of these relationships.Methods: This study included 100 consecutive patients who had coronary arterydisease diagnosed by coronary angiography. They were distributed according tosyntax score into: low(56 patients), moderate (25 patients) or high syntax score(19patients).In the all patients, carotid duplex U/S was done for the assessement of thecarotid IMT and the summation value of the carotid plaques dimensions(mm²). Alsobilateral lower limbs arterial duplex was done for assessment of CFA IMT and ABI .We studied the correlation between the numerical valvue of syntax score with thenumerical value of both carotid IMT and the summation value of carotid plaquesdimensions.We also studied the correlation between the numerical value of the syntaxscore and the numerical value of both CFA IMT &ABI.Conclusion : In our study, We concluded that in patients with carotid disease, therewas a significant positive correlation between the numerical value of carotid IMT andsyntax score with (P) value:0.002. There were also a significant positive correlationbetween the summation value of carotid plaques dimensions and the numerical valueof syntax score with (P) value :0.001. In PAD, there were a significant negativecorrelation between the numerical value of ABI and the numerical value of syntaxscore with (P) value:0.001 . There were no siginificant correlation between thenumerical value of CFA IMT and the syntax score with (P) value:0.769.