BACKGROUND፡ Multiple sclerosis (MS) is an immune mediated disabling neurological disorder. Very little is known about MS in Ethiopia. The objective of this study was to determine the prevalence of hypovitaminosis D and associated factors in cohort of MS patients in Ethiopia.METHOD: A cross-sectional observational study was conducted among 25 multiple sclerosis patients at Yehuleshet Specialty Clinic, Addis Ababa, Ethiopia.RESULTS: The prevalence of vitamin D deficiency was 96% (n=24). The average serum vitamin D was 14.8 (±10.4) ng/mL. The mean age was 35.8 (±10) years. Females accounted for 80% (n=20). Relapsing and remitting MS was the commonest variant. Motor, sensory, and mixed symptoms accounted for 40% (n=10), 20% (n=5), and 24% (n=6), respectively. Cold or hot weather and stress were reported as worsening factors in 24% (n=6). Relapse rate was 44% (n=11). Fatigue and seizure disorder were reported by 80% (n=20) and 16% (n=4) respectively. Steroid is the commonest prescribed medication for the patients. A negative correlation was found between serum vitamin D and age (r = -0.062, p = 0.7). Similarly, a negative association was observed between vitamin D and duration of illness (r = -0.311, p = 0.1). Fatigue was reported by those with moderate hypovitaminosis compared to those having severe hypovitaminosis (p=0.002). Seizure was reported more by those with vitamin D below 10ng/mL compared to those having above 10 ng/mL (p=0.004).CONCLUSION: Our study demonstrates a high prevalence of hypovitaminosis D in Ethiopian MS patients. Hypovitaminosis D was associated with increment in age and duration of illness.KEYWORDS: Multiple sclerosis, hypovitaminosis D, latitude, vitamin D, Ethiopia