During the past decade, several disease-modifying agents have been established and have become available for the treatment of multiple sclerosis. The disease-modifying agents could be grouped into immunomodulatory and immunosuppressive therapies altering the long-term course of multiple sclerosis. Therapy is now available for relapsing-remitting, secondary progressive and progressive-relapsing multiple sclerosis. Different disease-modifying agents became also available for the treatment of relapsing-remitting multiple sclerosis in Hungary which makes the therapeutic decision difficult. This overview might help to give an answer for different questions in the management of multiple sclerosis: Which agent to choose? When to initiate the therapy? Which dose to apply? Are the drugs safe? How long to treat the patients with immunomodulatory drugs? We give a review from the literature to assess the efficacy of disease-modifying therapies and to compare the data from phase three trials of interferon beta1b, two preparations of interferon beta1a or glatiramer acetate for the treatment of multiple sclerosis. We analyzed the efficacy and safety of these agents on physical, inflammatory and cognitive measures of disease activity. Comparison of study results indicated similar effects of immunomodulatory agents on relapse-related and inflammatory measures in relapsing multiple sclerosis. Interferon beta1a slowed the progression of disability in relapsing multiple sclerosis. One interferon beta1a preparation (intramuscularly injected) demonstrated efficacy in slowing progression of cognitive dysfunction. The interferons reduced relapses at early phase of secondary progressive multiple sclerosis, but their efficacy have not yet been proven in the later phase of secondary progressive multiple sclerosis without relapses. Mitoxantrone demonstrated efficacy in slowing the progression of disability in secondary progressive multiple sclerosis. All of the disease modifying agents are safe and tolerable, if the indication is correct and the patients are strictly controlled.