Objectives: The purpose of the study was to determine possible relationship between body mass index and clinical features (disease type, course and duration, treatment option and degree of disability) of the patients with multiple sclerosis. Influence of BMI on patients' quality of life was also researched in this study. Study Design: This study is designed as a cross-sectional study. Patients and Methods: The study recruited thirty patients undergoing treatment for multiple sclerosis at the Department for Demyelinating Diseases and the day hospital of Neurology Clinic at the University Hospital Center Osijek. Methods used in the study were an anonymous survey on demographic data, clinical features of the disease, and a standardized survey containing 36 questions pertaining to the assessment of the quality of life (SF-36). Results: Most patients (89 %) in the conducted study have a relapsing-remitting type of multiple sclerosis, while 57 % of participants have normal weight. The results indicated that the influence of body mass index on the clinical features of the disease and the patients' quality of life was not significant. However, in small sample size, the proportion of normal-weight patients undergoing treatment with ocrelizumab was significantly greater than overweight and obese patients. Moreover, the patients who reported having three meals a day had significantly better scores on the vitality section of the SF-36 survey. Conclusion: Our study revealed that there is no significant influence of body mass index on clinical features and quality of life of patients with MS. However, significantly better vitality in patients consuming three meals a day suggests a possible correlation between dietary habits and the quality of life of persons with MS. Further studies on a larger number of participants and during longer time frames are necessary to reach a more significant conclusion.