Vertebrobasilar insufficiency is the cause of cerebrovascular accidents in 20% of cases. There are few reports regarding spectral Doppler INDICES (SDIs) of vertebral arteries (VAs) normal BLOOD flow. The objective of this study was to provide basic reference data about SDIs of VAs normal BLOOD flow separately and in comparison with internal carotid arteries (ICAs) and common carotid arteries (CCAs) normal BLOOD flows SDIs. This cross-sectional study performed on 70 normal patients. Color Doppler sonography (CDS) and spectral Doppler sonography (SDS) of right and left VAs (RVA and LVA), right and left CCAs (RCCA and LCCA), right and left ICAs (RICA and LICA), were performed. The mean PSV, EDV, and RI values of RVA BLOOD flow were as 41.60±9.6 cm/s, 14.60±3.7 cm/s and 0.65±0.06, and the mean PSV, EDV and RI values of LVA BLOOD flow were as 42.20±10.2 cm/s, 15.20±4.2 cm/s, and 0.64±0.05, respectively. There was not statistically significant difference between the mean PSV, EDV and RI values of RVA and LVA BLOOD flows. The mean PSV and EDV values of VAs BLOOD flows were significantly lower than the values of CCAs and ICCAs BLOOD flows, respectively. The mean RI value of VAs BLOOD flows was significantly lower than the mean RI Value of CCAs BLOOD flows, but there was not statistically significant difference between the mean RI value of VAs BLOOD flows and the mean RI value of ICAs BLOOD flows.