Whether neuropsychological changes follow carotid artery surgery is unclear, in part because of complications by multiple perioperative variables. Therefore, we carried out a detailed analysis of patients who underwent carotid artery surgery in which we attempted to control for the most important variables by excluding patients with a preoperative stroke and by adopting a standard operative technique without use of intraoperative carotid shunts. Thirty inpatients with symptomatic carotid artery disease admitted for carotid endarterectomy were assessed with a comprehensive battery of neuropsychological tests administered immediately before and after (48-72 h) surgery. No carotid bypass shunt was inserted during the operation. The battery included dementia and depression screening tests, standardised neuropsychological measures including Verbal Fluency and the National Adult Reading Test, and a battery of contemporary computerised tasks designed to measure different aspects of memory and attention from the Cambridge Neuropsychological Test Automated Battery (CANTAB). No significant difference was found in the cognitive scores postoperatively as compared with the patients' preoperative scores or compared with scores of a control group matched by age and intelligence.