The objective of this study was to investigate the results of transcranial Doppler monitoring during tilt table tests in stroke patients with and without orthostatic hypotension. In stroke patients without orthostatic hypotension, the mean flow velocity was almost similar in both middle cerebral arteries and was stable during the test. In patients with orthostatic hypotension symptoms, a significant difference was found between the two hemispheres. Mean flow velocity in the damaged middle cerebral artery was lower in the supine position and stayed almost the same at 80 degrees standing. In the non-damaged middle cerebral artery, however, the mean flow velocity was much higher when supine and dropped in the standing position. These findings suggest that the appearance of orthostatic hypotension symptoms may be associated in post-stroke patients with decreased blood velocity in the damaged middle cerebral artery. Those patients are at a high risk of developing syncopal reactions and should be treated on the tilt table with caution, especially at the beginning of the rehabilitation.