Patients with multiple sclerosis (MS) experience higher mortality rates as compared to the general population. While the risk of intensive care unit (ICU) admission is also reported to be higher, little is known about causes of death CoD in critically ill MS patients.To study the causes of death (CoD) in the series of critically ill patients with MS verified by autopsy.We reviewed hospital electronic charts of MS patients treated at the neurological ICU of a tertiary care hospital between 2000 and 2015. We compared clinical and pathological CoD for those who were autopsied.Overall, 10 patients were identified (seven female; median age at death 65 years, range 27-80), and six of them were autopsied. The median MS duration prior to ICU admission was 27.5 years (range 1-50), and the median EDSS score at the time of ICU admission was 9 (range 5-9.5). The median length of ICU stay was 3 days (range 2-213). All the individuals in our series had experienced respiratory insufficiency during their ICU stay. The autopsy examination of brain tissue did not reveal evidences of MS lesions in one patient. In another patient, Lewy bodies were found on brain immunohistochemistry.Mortality in critically ill MS patients is largely driven by respiratory complications. Sporadic disparities between clinical and pathological findings can be expected.