Background: Internal carotid endarterectomy (CEA) is a method of stroke prevention in patients with severe internal carotid artery (ICA) stenosis. Patients with significant carotid stenosis tend to have lower cognitive performance than those without significant stenosis. This is believed to be due to hypoperfusion or ongoing microembolization to the brain. Methods: We evaluated 60 patients with at least 70% ICA stenosis with the RBANS test (Repeatable Battery for the Assessment of Neuropsychological Status, Czech research version), preoperatively and one month after endarterectomy. Results: Neuropsychological follow-up was completed by N = 57 patients one month after the procedure. At the group level, there was a significant improvement in Language, Attention, Delayed Memory and Total Scale Index Scores (p < 0.05). Conclusions: CEA not only decreases the long-term risk of ischemic stroke, but may also improve cognitive performance. In a small percentage of cases, there is higher risk of embolic stroke and silent microembolization due to surgery, which may have a negative impact on cognitive function. However, we did not detect any cognitive impairment after CEA in our patients.