Since vascular risk factors that predispose to vertebrobasilar ischemia are common findings in elderly, cervical spondylosis-which is also common in such age group-as a cause of vertigo is sometimes considered as a myth. The purpose of this study is to investigate the effect of cervical spondylosis on blood flow velocity of VAs during cervical rotation and to identify the possible association of vertigo with the decreased blood flow velocity through VAs during head rotation in these patients. The incidence of cervical spondylosis was estimated in patients with and without vertigo. Patients with vertigo proved to have spondylosis are further compared with patients having spondylosis but not complaining of vertigo and patients who neither have spondylosis nor complain of vertigo who served as controls. Plain cervical radiography was used to evaluate cervical degenerative changes using cervical degenerative index. Color duplex sonography was used to measure vertebral artery blood flow with the cervical spine in the neutral position then with 60° rotation and 30° extension to measure the opposite vertebral artery. A significantly higher prevalence of cervical spondylosis was found among patients complaining of vertigo than those in non-vertigo group (71.4% vs. 32.9%, respectively). Furthermore, among patients with cervical spondylosis, patients having vertigo showed significantly more evident degenerative changes (P = 0.003). Despite Doppler ultrasound examination with head in neutral position was similar in all groups; cervical spondylosis patients with vertigo had statistically significant lower blood flow parameters with contralateral head rotation in the left and right vertebral arteries than cervical spondylosis patients without vertigo and controls. The decreased vertebral artery blood flow that occurs with cervical rotation can be observed in patients with cervical spondylosis. In patients with high-grade cervical spondylosis with more extensive osteophyte formation, the decreased blood flow becomes prominent and symptomatic presenting as vertigo.