Mitoxantrone was originally developed as an antineoplastic agent. However, it is currently used as an immunosuppressant in the treatment of multiple sclerosis (MS). A series of European studies over a 10-year period have revealed the clinical benefits and tolerability of mitoxantrone. On the basis of the favorable findings reported by the above mentioned studies, the FDA approved the use of mitoxantrone for reducing neurologic disability and/or the frequency of clinical relapses in patients with secondary progressive MS, progressive relapsing MS, or worsening relapsing-remitting MS but not for treating patients with primary progressive MS. The therapeutic modalities available in Japan are very limited. Interferon beta (IFN-beta), which is an immunomodulatory drug, is the only drug approved in Japan for treating MS; however, it is only partially effective or rather ineffective for treating patients with rapidly worsening or fulminant MS. Our pilot studies confirmed the benefits of mitoxantrone in Japanese patients with MS, and in this study, we review its potential appliciation for the treatment of MS by Japanese neurologists.