Background:Previous studies had linked obesity to the pathogenesis and risk of multiple sclerosis (MS) but little is known about its association with disease course. Objective: This study aimed to assess the frequency of obesity in MS patients and its relation to disease disability. Methods: A cross-section study included 60 patients with clinically definite relapsing remitting multiple sclerosis was selected from the inpatients wards and outpatients clinic of Neurology Department, Zagazig during the period from March 2020 to September 2020. All patients underwent a thorough physical and neurological examination, as well as laboratory and radiographic tests. Obesity was diagnosed if body mass index (BMI) ≥30. The Expanded Disability Status Scale (EDSS) was used to assess disease disability. Patients were divided into 2 groups (obese and non-obese) according to BMI. Results: Obesity frequency was 43.3% (26 MS patients). Obese MS patients had higher disease duration (6.23 ± 4.65) and more disease disability (EDSS= 4.0 ± 2.21). There was positive correlation between BMI with EDSS, disease duration, number of relapses and total cholesterol. Multiple regression analysis showed that EDSS was independently associated with obesity in MS patients.Conclusion:There was a high frequency of obesity in MS patients. Disease disability (EDSS) was significantly associated with obesity in MS patients. Obesity screening should be a regular component of MS management. Keywords: Multiple Sclerosis, Obesity, Disability, EDSS, BMI.