The clinical features,disease course and long term prognosis of early onset multiple sclerosis(EOMS)are variable.A preponderance of female sex,a high incidence of visual and brainstem symptoms at onset and a relapsing-remitting disease course with slower progression rate all have been considered relatively frequent in this subgroup of MS patients.Unfortunately,follow-up in previous studies has usually been limited to less than 10 years,precluding general statements on the long term evolution and prognosis in EOMS.In this retrospective study of EOMS with a substantially longer follow-up of 20.8 years,clinical characteristics,disease course and long term prognosis are described in 49 EOMS patients.In a representative subgroup of 28 patients disability was scored using Kurtzke’s Functional System(FS)and Expanded Disability Status Scale(EDSS).The mean period of follow-up for these patients was 28.7 years.The present study confirms that several specific clinical characteristics can be identified in EOMS patients,such as a mainly relapsing-remitting disease onset and frequent presentation with brainstem-cerebellar dysfunction(28.6 %),pyramidal symptoms(18.4 %)and optic neuritis(14.3%).However,after a long period of follow-up the overall disease course and prognosis do not seem to differ from that in adult onset MS.By consequence a young age at onset in MS cannot be considered a favourable prognostic factor. The clinical features, disease course and long term prognosis of early onset multiple sclerosis (EOMS) are variable. A preponderance of female sex, a high incidence of visual and brainstem symptoms at onset and a relapsing-remitting disease course with retard progression rate all have had considered relatively frequent in this subgroup of MS patients. Unfortunately, follow-up in previous studies has usually been limited to less than 10 years, precluding general statements on the long term evolution and prognosis in EOMS. this retrospective study of EOMS with a substantially longer follow-up of 20.8 years, clinical characteristics, disease course and long term prognosis are described in 49 EOMS patients. In a representative subgroup of 28 patients disability was scored using Kurtzke’s Functional System (FS) and Expanded Disability Status Scale (EDSS) The mean period of follow-up for these patients was 28.7 years. The present study confirms that several specific clinical characteristics can be ident Ified in EOMS patients, such as a mainly relapsing-remitting disease onset and frequent presentation with brainstem-cerebellar dysfunction (28.6%), pyramidal symptoms (18.4%) and optic neuritis (14.3%). However, after a long period of follow- up the overall disease course and prognosis do not seem to differ from that in adult onset MS.By consequence a young age at onset in MS can not be considered a favourable prognostic factor.