OBJECTIVE This study evaluated the hemodynamic effects of carotid artery stenting (CAS) on cerebral blood flow velocity (CBFV) in patients with carotid artery stenosis, before, 3 d, and 3 months after the procedure using transcranial Doppler ultrasound (TCD). METHODS The study included 36 patients with atheromatous carotid artery stenosis. Cerebral computed tomography (CT) or magnetic resonance imaging (MRI) was performed in every patient, and carotid stenosis was evaluated using duplex sonography, CT, and MRI angiography before the procedure. To obtain baseline values, the CBFV was evaluated 1 d before CAS. Follow-up TCD evaluations were performed 3 d and 3 months postoperatively. RESULTS The median degree of internal carotid artery (ICA) stenosis in the participants was 90% (range 50%-99%). The median CBFV at the anterior cerebral artery (ACA) was significantly lower on the ipsilateral side than on the contralateral side before stenting; however, there were no significant differences in CBFV in the ipsi and contralateral middle cerebral artery (MCA). The median CBFV in the ipsilateral MCA increased significantly 3 d after the procedure and remained higher than the basal values after 3 months. CONCLUSIONS We observed significant increases in the median CBFV and pulsatility index (PI) in the MCA bilaterally, especially on the stented side, measured 3 d and 3 months after stenting in patients with severe ICA stenosis.