Many neurologic scales have been used for clinical evaluation of multiple sclerosis, but there is no consensus about which one is the most appropriate to assess evolution and point to a new relapse. The Expanded Disability Status Scale (EDSS) has been the most commonly used. We analyse the reliability of two scales: the EDSS and Neurologic Rating Scale (NRS) in 302 multiple sclerosis patients. It is shown that NRS is a more sensitive scale than EDSS to disclose clinical changes (22.1% of cases). Changes in NRS were more evident in patients with EDSS 3.0 and 3.5. We comment on these findings and suggest that both scales should be employed in multiple sclerosis treatment trials.