OBJECTIVES: Magnetic resonance angiography (MRA), three-dimensional computed tomography angiography, and cerebral angiography may be used to assess intracranial vertebrobasilar stenosis. However, these examinations cannot be performed at patients' bedsides. Our purpose was to develop a new bedside method to assess intracranial vertebrobasilar arterial stenosis. METHODS: We developed the new method using carotid duplex ultrasonography combined with the head-up test. A total of 141 subjects admitted between June 1, 2017 and March 31, 2019 were enrolled in this study. We calculated vertebral arterial peak systolic velocities (PSVs), end-diastolic velocities (EDVs), and mean velocities (MVs) at 0°, 16°, and 30° head-up angles. Vertebrobasilar arterial stenosis was confirmed using MRA. RESULTS: We excluded 28 subjects and included data for 113 subjects and 226 vessels in the final analysis. Cervical vertebral arterial PSV, EDV, and MV gradually decreased from 0° to 30° only in stenotic intracranial vertebral arteries. Sensitivity (probability of detection) was 75.5% and specificity (true negative rate) was 79.7% when EDV at the 30° head-up angle decreased ≥19.5% from the initial 0° head-up angle. Specificity was better (86.4%; sensitivity: 69.4%) when EDV was <9.1 cm/s at the 30° head-up angle. CONCLUSION: This new method easily detects intracranial vertebrobasilar arterial stenosis.