A longitudinal, population based study of life expectancy in multiple sclerosis was performed in the county of Møre and Romsdal, Norway during the period 1950-84. A total of 251 patients with multiple sclerosis (110 men, 141 women, mean age at onset of disease 33.6 years) were included. The mean follow up time was 18.1 years. At the end of the study period 70 patients had died. Fifty four (77.1%) of these had multiple sclerosis as the underlying or contributing cause of death on the death certificates. Young age at onset, initial remitting clinical course, and the presence of sensory symptoms at onset were significantly associated with longer survival.