Study Objectives: Sleep disorders are seen in patients with demyelinating disease (DD) more often than in the general population. Combination of physical and psychological factors such as pain, spasms, nocturia, depression, anxiety, or medication effects could contribute to sleep disruption. Frequently, these disturbances have a major impact on health and quality of life of patients. The aim of this study was to estimate the prevalence of sleep disorders in patients seen in the DD consultation. Methods: 240 patients; mean age 43 years, 187 women; 163 patients with multiple sclerosis (MS): 144 relapsing-remitting, 19 progressive forms, 36 clinically isolated syndrome, 26 radiological isolated syndrome, and 15 patients with others DD. All participants completed questionnaires: Pittsburgh, Epworth, and Stanford scales, indirect symptoms of RLS and Obstructive Sleep Apnea, Fatigue Severity Scale, and Multiple Sclerosis Quality of Life-54. Results: Moderate/severe insomnia 12.5%, OSA 5.8%, RLS 9.6% (confirmed 3 cases), narcolepsy 0, fatigue (> 4) 24.6%. Physical QoL 66.6 ± 19.6, Mental QoL 66.1 ± 21.9. Patients with an established diagnosis showed higher scores on insomnia compared to the group of CIS and RIS (F = 3.85; p = 0.023), no differences were in the other parameters. Fatigue showed high correlation with insomnia (r = 0.443; p < 0.001), RLS (r = 0.513; p < 0.001), and sleepiness (r = 0.211; p = 0.001). None of the variables included in the regression model were shown to be predictors of Physical and Mental QoL. Conclusions: A high percentage of our sample sleeps well. Emphasize the low prevalence of sleep disorders (insomnia, fatigue, RLS, etc). We detected an overestimation in the RLS questionnaire and the low QoL recorded. I NTRO DUCTI O NMultiple sclerosis (MS) is the main cause of a chronic traumatic disability among young adults (between 20 and 50 years of age) with neurological disorder. MS is an inflammatory autoimmune disease of the central nervous system (CNS) resulting in myelin destruction and axonal degeneration in the brain and spinal cord.Eighty percent of patients present a relapsing-remitting subtype, characterised by clearly defined episodes of neurological dysfunction (relapses) separated by periods of relative clinical stability (remissions). In the majority of untreated cases, relapsing-remitting MS evolves into a secondary-progressive phase during which the subject experiences a gradual, insidious deterioration, usually in the form of paraparesis, hemiparesis, or dementia. A primary-progressive subtype occurs in a smaller percentage of patients, characterised by a slow deterioration in neurologic function from onset, without distinct relapses.The clinical manifestations of MS are provoked by multifocal demyelination and damage to axons in multiple neurological functional systems; these are known as deficit symptoms (or negative symptoms). Other manifestations of MS, such as neuropathic pain and paroxysmal phenomena, are derived from functionally inappropriate axonal responses, which are ...