Interferon beta (IFNbeta) and glatiramer acetate (GA) showed a relevant impact in modifying the clinical course of relapsing-remitting multiple sclerosis. However, not all treated patients experience a satisfied response to therapy in terms of suppression of relapse and slowing disability progression.At the present time none of the proposed criteria of response to disease modifying therapies (DMTs) have been validated. Clinical parameters, such as relapse rate and disability progression assessing with EDSS scale, may represent two useful indicators of therapeutic response, but their value in predicting the long-term response to DMTs is weak.