Cognitive impairment is a frequent feature in multiple sclerosis patients. To assess its evolution in comparison with clinical and neuroradiological evolution, we followed up 57 multiple sclerosis patients over a 3-year period. During this time EDSS deteriorated significantly but not the MRI lesional load nor the cognitive test performance; nevertheless both at the beginning and at the end of the follow-up neuropsychological results showed a significant correlation with both EDSS and lesional load. No clinical or paraclinical features could reliably predict neuropsychological evolution.Copyright Lippincott-Raven Publishers