Patients with MS report sleep disturbances more frequently than the general population. Besides specific sleep disturbances, many other conditions could impair nocturnal rest in this population. In addition, information regarding the role of disrupted sleep on quality of life (QoL) in patients with MS is lacking. This study, reported in Sleep Medicine journal, was performed to bridge this gap. A total of 120 patients with MS were enrolled into the study. The Pittsburgh Sleep Quality Index (PSQI), the Charlson Comorbidity Index (CCI), and the Italian version of the 36-item Short Form (SF-36) were used to assess quality of sleep, comorbidity and QoL, respectively. Nearly half (47.5%) of patients with MS were classified as “poor sleepers,” having significantly higher EDSS (average 3.1 vs. 2.3) and CCI scores (average 0.19 vs. 0.03) than “good sleepers.” In addition, pain due to MS was more common among “poor sleepers” (33.3% vs. 17.7%). Scores for each domain of the SF-36, and the mental component summary (MCS) and physical component summary (PCS) scores were significantly lower in poor sleepers than in good sleepers. Of the different variables associated with MCS, the only independent predictors of mental status were: presence of sexual and/or bladder dysfunction and global PSQI score. The independent predictors for physical status (PCS) were age, EDSS score, and global PSQI score. Poor sleep is common in patients with MS, representing an independent predictor of QoL. Patients with MS who are poor sleepers should receive immediate assessment and treatment, bearing in mind that, in addition to specific sleep disturbances, other clinical conditions (both related and unrelated to MS) can disrupt nocturnal sleep. (Available from: http://www.pubmed.gov PMID: 18207453)