Aim: In this study, we aimed to investigate the relationship between AKW and the severity of CAD in patients with stable CAD.Stable coronary artery disease (CAD) patients coronary artery disease severity is determined invasive coronary angiography scoringsystems as SYNTAX and Gensini scores. Therefore, there is a need for noninvasive and easy to apply methods for determining theseverity of the disease in stable CAD. Aortic knob width (AKW) is a measurable radiographic structure from chest X-ray.Material and Methods: The study included 168 patients with stable CAD ranging from 18 to 70 years old after exclusions criteriaapplied 114 patients examined. Patients grouped according to coronary artery vessel diameter narrowing above and below 70%.Patients Baseline characteristics, physical examination, medical treatments and laboratory findings recorded. The severity of CADwas evaluated by SYNTAX and Gensini scores. AKW measurement was also evaluated.Results: The two groups were statistically similar with respect to demographic properties and laboratory findings. Prior medicationswere similar between the groups. Furthermore percentage of diabetes mellitus and CRP levels were significantly different betweengroups (48.4%, 22% p:0.004 , 6.3±12, 2.4±4 p:0.049 respectively). AKW was significantly higher in group 1 compared to group2 (41.1±6.2, 37.3±5.2; p=0.007). AKWs were correlated with Gensini and SYNTAX scores (r=0.25;p=0.007 and r=0.26;p=0.006respectively). In a ROC analysis, the area under the curve value of AKW for CAD was 0.648 (95% CI: 0.544-0.752, p<0.008). Theoptimal cut-off value of AKW measurement for CAD was 36.6 mm with 73% sensitivity and 61% specificity. In a multivariate analysis,independent predictors for SYNTAX score > 22 were; DM (Odds ratio [OR]: 6,088, 95% CI: 1.617-22.927; P= 0.008) , AKW (OR: 1.122,95% CI: 1.024-1.229;P= 0.013).Conclusion: To demonstrate the severity and complexity of coronary artery disease in stable coronary artery disease, noninvasiveand simply calculated AKW can be used instead of invasively calculated the calculated SYNTAX and Gensini scores.