The etiology and patogenesis of multiple sclerosis are unknown, but the abnormalities in the immune system have an important role in mediating multiple sclerosis attacks. The rationale for immunosupressive treatment used in the attacks such as IVMP, is the suppress the inflammatory reaction of the immun system in order to prevent or stop the process of demyelination. In this study, clinical and neurophysiological parameters (somatosensory, visual, brainstem auditory and motor evoked potentials) were assessed before and after the treatment in order to detect of efficacy of the IVMP treatment. We administrated 1000mg /day IVMP to the 23 patients with definite MS during five days. After treatment, EDSS significantly improved in 15 patients, but no electrophysiological tests in any patients.