Survival from onset of symptoms was calculated for two series of MS patients, a population-based epidemiologic series from southern Lower Saxony of 224 cases, and a revised hospital series of 1429 cases from 11 neurologic centers throughout the Federal Republic of Germany. Median survival for the epidemiologic series was 35-42 years, with no finer estimate possible. Observed survival was 3/5 expected survival after 35 years of illness. Survival in this series was similar to that from two other population-based reports. No significant difference was found between the sexes, though patients with onset at age 35 + had a significantly shorter survival than those with onset at age under 35 years. The much larger hospital series, where median survival was 30 years, demonstrated significant differences separately favoring females and young onsets. However, the ratios of observed to expected survival from population life tables were strikingly similar among all four subgroups defined by sex and age at onset. While overall there is a substantial reduction in the expectation of life in MS, the differential survival by sex and age appears to be a reflection of the expected survival by sex and age per se, and not that of the disease.