To evaluate the effect of different frequencies of repetitive transcranial magnetic stimulation( rTMS) on cognitive function in stroke patients. The study was conducted on 30 right handed stroke patients with right sided hemiparesis and history of stroke from 6 to 20months. They were divided into two equal groups; group I receiving 10Hz frequency of rTMS and group II receiving 5Hz in 10 sessions. Each session included 6 trains and 7min duration. They were evaluated by Addenbrooke Cognitive Examination Revised Test (ACER) and transcranial doppler (TCD) for blood flow velocity (BFV) in affected middle cerebral artery pre and post- treatment with rTMS. There was a significant differences in blood flow velocity in the affected side (left MCA) in both groups (p<0.05) with improvement of (20.02%, 11.41%) respectively. There was also a significant differences in total ACER Test in both groups (p<0.05) with improvement of (33.5%, 25%) respectively. A significant positive correlation (p<0.05) between improvement percentage of blood flow and improvement percentage of total ACER Test in both groups was found. This study showed significant increase in the BFV in the MCA and the total ACER score after applying high frequencies of rTMS, supported by many authors. High frequency rTMS plays a major role in improving the cognitive impairment in stroke patients. Repetitive transcranial magnetic stimulation should be considered a future cornerstone in neurorehabilitation and therapy.