To compare the usefulness of multiple sclerosis functional composite (MSFC) to the Expanded Disability Status Scale (EDSS) in assessing functional changes related to relapse. A prospective 12-week follow-up study after relapse was conducted among 14 multiple sclerosis (MS) patients treated with oral high-dose (1 g) methylprednisolone for 3 days. MSFC and the EDSS were assessed on day 0, before treatment and, 1, 4 and 12 weeks afterwards. In relapses, EDSS (2.5 +/- 1.2 to 3.8 +/- 1.0) and z-score of the MSFC (0.15 +/- 0.58 to -0.59 +/- 0.70) worsened. After 1 week of treatment, the EDSS improved (3.3 +/- 1.2; P = 0.002) while the MSFC did not change significantly. At week 4, EDSS improvement was maximal (2.8 +/- 1.3; P = 0.001). At week 12, EDSS remained stable whereas z-score continued improving (0.26 +/- 0.74). z-9peg-hole-test was the most sensitive subtest. There was correlation between baseline values of both scales (-0.620, P < 0.05) and between changes due to relapse (-0.535, P < 0.05). 78.5% of patients had improved at week 4 (35.7% at week 1). There were no serious adverse effects. MSFC and the EDSS were sensitive to changes due to relapses, although the dynamics for restoring baseline function were different. Our data support the usefulness of both scales in clinical trials, providing complementary information about outcome of MS patients with relapses.