Fenestrations of vertebral arteries are considered to be rare abnormalities observed in angiographic and autopsy studies. They result from vascular abnormalities that occur during the embryological development of vertebral artery. Fenestrations of the vertebral artery are vascular structures having 2 different lumens and endothelium layers, sharing either the same or separate adventitia layers. As a result of the carotid Doppler ultrasonography performed on a 65-year-old woman applying to the Neurology Clinic of Cumhuriyet University Faculty of Medicine, Research and Practice Hospital with the complaints of vertigo and numbness in the head, a plaque leading to 60% stenosis in the right internal carotid artery, close to the place of initiation was seen. The patient, whose vertebral artery lumen structures and calibrations have found to be normal in the Doppler ultrasonography of vertebral artery, was scheduled for double-sided selective carotid and vertebral artery angiography. With the performed digital subtraction angiography imaging method, an atheroma plaque, extending to internal carotid artery proximal starting from sinus caroticus through the right internal carotid artery and leading to 50% stenosis, having the appearance of an ulcer, was observed. In the vertebral artery angiography of the case, while the right vertebral artery was found to be normal, fenestration in the upper cervical segment was observed in the left vertebral artery. This situation has been presented in this paper with radiological and embryological evaluation.