Multiple Sclerosis (MS) is a chronic disease affecting the central nervous system, exhibiting autoimmune and neurodegenerative properties. Neurological deficits, mobility limitations, and decreased muscle strength are commonly observed in MS patients as the disease progresses. The literature indicates that low physical activity levels and neurological deficits in individuals with MS can lead to decreased muscle mass and functional losses. Sarcopenia is a condition characterized by decreased skeletal muscle mass and strength associated with aging and chronic diseases, and studies on the prevalence of sarcopenia in MS patients are limited. Recent studies have revealed a high prevalence of sarcopenia in MS patients, which can have negative effects on physical performance, quality of life, and disease progression. Low muscle mass in MS patients can accelerate the loss of motor function and increase the level of disability. Additionally, nutritional deficiencies and low protein intake seen in MS patients are among the factors that accelerate muscle loss. Studies examining the relationship between MS and sarcopenia in the literature emphasize the importance of early diagnosis and intervention to improve patients' quality of life and functional independence. Factors such as muscle strength, physical activity level, and nutritional status should be assessed to determine the risk of sarcopenia in MS patients. This study was designed to determine the prevalence of sarcopenia in patients with Multiple Sclerosis (MS) and to examine the relationship between sarcopenia and fatigue, disability level (EDSS), nutritional status, and physical activity level. In this context: * The prevalence of sarcopenia in MS patients will be determined, * The relationship between sarcopenia and muscle strength, physical performance, and body composition will be evaluated, * The effects of nutrition and physical activity on sarcopenia in MS patients will be investigated.