Aims: Previous studies have reported that sleep disorders are frequently seen in patients withmultiple sclerosis (MS). In this study, we aimed to investigate the frequency and related factorsof sleep disorders in these patients. Methods: In this cross-sectional study, sleep disorder was assessed using the Pittsburgh SleepQuality Index (PSQI) and Epworth Sleepiness Scale (ESS). Fatigue, generalized pain, anxiety,depression symptoms, restless legs syndrome (RLS) and urinary dysfunction were evaluatedusing the Fatigue Severity Scale (FSS), visual analogue scale (VAS), Hospital Anxiety andDepression Scale (HAD), and RLS Rating Scale and Scales for Outcomes in Parkinson’s disease Autonomic. Logistic regression analysis was used to assess the potential associations betweena sleep disorder diagnosis and the investigated conditions. Results: Fifty-six patients [age (mean±standard deviation): 36.2±2.8 years; female: 30.4%] wereincluded. Fifty percent of the patients scored 5 or more according to PSQI. ESS, HADS, FSS andVAS scores of patients with sleep disorder were significantly higher than those of patients withno sleep disorder (p=0.002, p=0.001, p<0.001, and p<0.001, respectively). Logistic regressionanalysis showed significant associations between sleep disorder and fatigue [Odds ratio (OR):6.54 (95% confidence interval (CI): 1.08-39.57, p=0.041)], depression [OR: 9.82 (95% CI: 1.47- 65.6), p=0.018], and generalized pain disorders [OR: 1.79 (95% CI: 1.23-2.3), p=0.002]. Conclusions: Our results show that half of the patients with MS suffer from sleep disorders.Sleep disorders in this group are associated with fatigue, depression, daytime sleepiness,common body pain, and immunomodulatory treatment.