PURPOSE: Vertebrobasilar ischemia has been attributed to a reduction of net vertebral artery flow volume. This study was to establish the reference values for the flow volume of the vertebral artery using color Doppler sonography in the normal Korean adults. MATERIALS AND METHODS: Thirty five normal Korean adults without any underlying disease including hypertension, hyperlipidemia, diabetes, heart disease, obesity (body mas index > 30), or carotid artery stenosis was included. There were 17 males and 18 females, age ranged from 20 to 53 years (average = 32.86 years). Flow velocities and vessel diameters were recorded in the intertransverse (V2) segment, usually at C5-6 level, bilaterally. The flow volume (Q) was calculated. (Q =time averaged mean velocity x cross sectional area of vessel) RESULTS: A lower Flow velocity and smaller vessel diameter were measured on the right side compared to those of the left side, resulting in a lower flow volume. The calculated flow volumes using the equation were 77.0+/-39.7 ml/min for the right side and 127.61.0 ml/min for the left side (p=0.0001) while the net vertebral artery flow volume was 204.61.8 ml/min. Decrease in the vertebral artery flow volume was statistically significant with advanced age. (r=-0.36, p=0.032). Vertebral artery blood flow volume was 191.209.19 ml/min in male, and 217.288.67 ml/min in female (p= 0.6). The normal range for the net vertebral artery flow volume defined by the 5th to 95th percentiles was between 110.06 and 364.1 ml/min. CONCLUSION: The normal range for the net vertebral artery flow volume was between 110.06 and 364.1 ml/min. Vertebral artery flow volume decreased with the increase of age. However, gender did not affect the blood flow volume.