Motor evoked potentials (MEP) were recorded in 23 patients with definite relapsing multiple sclerosis before and after treatment with a short course of high dose of methylprednisolone. MEP were performed together with clinical examination just before treatment, and 6 and 60 days later. The following results were observed: (1) a statistically significant relationship between the corticospinal deficit and the alteration in MEP, (2) a significant improvement in latency of MEP by day 6, (3) a significant correlation between the change in the Kurtzke disability scale rating and the improvement in MEP. The results provide further evidence for the possible effectiveness of short courses of high dose corticosteroids in the treatment of relapses of multiple sclerosis and the usefulness of MEP in its assessment.