In recent years, the usefulness of interferon beta and glatiramer acetate in the treatment of relapsing-remitting multiple sclerosis (RRMS) has been established. Interferon beta has also been shown to be efficacious in secondary-progressive multiple sclerosis (SPMS) as well as in patients with isolated syndromes at risk to develop clinically definite multiple sclerosis (MS). Mitoxantrone is another disease-modifying drug that is available for SPMS and severe cases of RRMS. The clinical utility of disease-modifying agents in MS will be reviewed with respect to the anti-inflammatory, immunomodulatory, and immunosuppressive treatments that are currently available. Symptomatic therapies will not be considered.