Aim: To measure the bony carotid canal diameters and to determine whether the variations of bony carotid canal width could be an indicator of cerebral vascular abnormalities and variations. Material and Methods:Seven-hundred neck-brain CT angiographies were assessed retrospectively. Of the patients, 283 (40.4%) were women and 417 (59.6%) were men. Bilateral bony carotid canal diameter was measured. Cerebral vascular variations and aneurysms were recorded.Results: Normal canal diameter on the right, in all patients was 5.631±0.502mm, in males 5.797±0.475mm and 5.388±0.441mm in females; on the left side, 5.666±0.512mm overall, 5.825±0.492mm in males and 5.432±04.49mm in females (p=0.039, <0.001 and <0.001 consequently).In vascular hypoplasias, in all other vascular agenesias other than posterior communicating (Pcom) artery, in Moyamoya disease, in anterior and middle cerebral artery aneurysms the canal is narrow.In the presence of fetal originated vessels, in dolichoectasias of vessels, except PCom, in all anterior communicating artery (ACom) variations and aneurysms, in internal cerebral artery aneurysm the canal is wide.PCom agenesia, anterior cerebral artery A2 trifurcation and ACom fenestration is accompanied by narrow canal on the right and wide canal on the left. Conclusion:Abnormal canal diameter may indicate to vascular variation or abnormaliti. The increased incidence of aneurysm in carotid canal anomalies implicates of the necessity of further studies with larger groups.