In order to assess mean diameters and blood flow velocities (BFV), Color Doppler Flow Imaging (CDFI) of vertebral arteries (VA) was performed. Five hundred and ninety six persons without carotid disease or symptoms related to vertebrobasilar system were analyzed by CDFI of VA. Mean right VA diameter was 3.37 +/- 0.6 mm and left 3.55 +/- 0.61 mm. Women had thinner VA (p < 0.05). Left VA was wider (p < 0.05). Mean right BFV was 48.31 +/- 14.09 cm/s and left 48.93 +/- 13.94 cm/s. Females had higher BFV (p < 0.05). BFV didn't very with age (p > 0.05). The VA hypoplasia was present in 2.34%, asymmetry in 15% (left VA dominant in 64%). Visualisation of V1 and V2 segment was possible in 100% and of the origin in 81.7% on the right, and 80.7% on the left side. CDFI is a reliable method for evaluation of VA. Left VA was wider. Women had thinner VA. Hypoplasia was present in 2.34% and asymmetry in 15%.