Pulsed wave 2 MHz Doppler with acoustical focusing was used to obtain blood flow velocity recordings through the intact cranium in 11 patients with occlusive disease of major intracranial arteries. Increased blood flow velocities were recorded from stenoses of the carotid siphon and of the middle cerebral, anterior cerebral and basilar arteries. A clear, inverse relationship existed between angiographical residual lumen diameter and flow velocity. The Kendall rank correlation coefficient (Tau) was -0.89 (p = 0.0001). Transcranial Doppler is a useful means for evaluating patients with this disorder.