Introduction: Stroke is one of the most severe complications after Coronary artery bypass grafting (CABG) and is associated with high rates of morbidity and mortality. Hypothesis: We aimed to define the relationship between extracranial and intracranial carotid artery stenosis and the risk of stroke after CABG. Methods: A retrospective analysis of 1245 consecutive patients who underwent coronary artery bypass grafting (CABG) in our institution from March 2015 till March 2017 was performed. All of them had carotid duplex ultrasound as a routine preoperative assessment. Those patients who had severe extracranial carotid stenosis (>70%), underwent computed tomography angiogram of head and neck cerebral vessels. Our analysis was mainly focused on assessing the relation between incidence of post-CABG stroke and severity of intra and extra cranial cerebral atherosclerosis. Results: Of the 1245 patients who underwent coronary artery bypass grafting(CABG) the routine preoperative carotid Doppler revealed severe extracranial carotid artery stenosis of >70% in 160 patients, who eventually underwent computed tomography angiogram which has shown both extra and intracranial cerebral vascular stenosis in 124 patients. Total number of patients who had post CABG strokes are 42 (3.37%), out of which 39 (3.13%) had extensive extra and intracranial vascular stenosis whereas only 3 (0.24%) had isolated extracranial vascular stenosis. Patients with extensive extra and intracranial cerebral atherosclerosis has high rate of in-hospital strokes (within 14 days) compared with patients with isolated extracranial atherosclerotic disease. Conclusion: Extensive atherosclerosis including intra and extracranial cerebral arteries are major risk factors for stroke in patients undergoing CABG. Pre-operative assessment of both intra and extracranial cerebral arteries increases the probability of risk assessment in high risk CABG patients.