Patients with multiple sclerosis (MS) have multiple causes of poor sleep and potential triggers may relate to MS-related symptoms, co-morbidities and adverse effects from medication. Sleep disorders may occur independently of demographic factors, gender and clinical condition. The real frequency of sleep disturbances in MS and their impact on the patients' quality of life are unknown. The prevalence of sleep problems in the population with MS ranges between 47 and 62% and is more frequent in women, as well as having a higher risk of mortality. High psychological burden has been associated with poor sleep and with increased risk of co-morbid conditions such as heart disease, obesity, dyslipidemia and diabetes, which may have a profound impact on long-term health. The poor sleeping patients with MS were more likely to report fatigue and sleepiness. Insomnia is present in mood disorders, restless leg syndrome (RLS), pain, nocturia and obstructive sleep apnea (OSA), in patients with MS. All the symptoms are intermixed, and it is not possible to discern the precipitating factor or the perpetuating factor. Clinicians should routinely ask about sleep when forming a comprehensive care plan for patients with MS. Sleep specialty referrals should be considered for management of conditions that require polysomnography (PSG) diagnosis.