Background: Primary sleep disorder, especially, obstructive sleep apnea (OSA), are noted to occur in MS patients at higher frequency than the general population. Objectives: Our objectives are: (1) To assess the frequency of OSA risk among MS patients. (2) To evaluate the relationship between OSA risk and self-reported fatigue and sleepiness. (3) To evaluate the relationship between OSA risk and clinical disability, radiological findings and treatment status. Methods: We enrolled 124 patients with multiple sclerosis, there were 53 men and 71 women with mean age (31.12 ± 7.48) All participants completed questionnaires: STOP-Bang, Berlin, Fatigue Severity Scale (FSS) and Epworth sleepiness scale (ESS) and their disability was assessed using Expanded Disability Status Scale (EDSS). Results: Among the completed surveys, 46.8% screened as high risk for OSA based on STOP-BANG questionnaire, and 45.2% based on Berlin questionnaire. About 64.5% of subjects screened positive for fatigue using FSS and 38.7% reported excessive day time sleepiness. Comparing MS patients diagnosed with high risk of OSA and those without, there was significant difference between the two groups regarding age (P<0.001), gender (P<0.001), disease duration, (P=0.04), presence of brainstem lesions (0.04) and disease modifying therapy (DMT) use (P=0.002). ESS and FSS positive scores were each significantly correlated with positive STOP BANG and Berlin outcomes (p<0.001). EDSS showed significant correlation with positive STOP-Bang and Berlin scores. Conclusions: OSA risk appears to be high in MS patients with increased risk of fatigue and increasing disability.