The purpose of this study was to test the interexaminer reliability of Doppler ultrasound (US) velocimeter examination of vertebral arteries during contralateral cervical rotation. Vertebral arteries from 20 adults were insonated using a bidirectional Doppler velocimeter at the suboccipital portal (standard technique) and C2 transverse process level (new technique) during contralateral cervical rotation. The data obtained by two examiners, regarding persistence or major reduction in Doppler signals, were compared. There was 93% agreement between the data from the two examiners, and the kappa score was 0.78 at p = 0.05. These results provide evidence to support the interexaminer reliability of bidirectional Doppler velocimeter examination for the purpose of assessing the effects of contralateral rotation on vertebral artery blood flow. (C) 2000 World Federation for Ultrasound in Medicine & Biology.