INTRODUCTION: Multiple sclerosis (MS) is a neurological demyelinating disease of the central nervous system manifested by pronounced heterogeneous symptoms. Peculiarities of the onset, progression rate, and severity of syndromes are different in different age groups. An increase in the frequency of exacerbations, high degree of disability of patients in different age groups evidence insufficient effectiveness of the conducted pathogenetic therapy. Due to a wide choice of multiple sclerosis disease modifying drugs (MSDMDs), it is important to study the clinical and neurological characteristics of patients with MS in different age groups with the aim of further developing an individual approach to treatment. AIM: To study clinical and neurological features and effectiveness of pathogenetic therapy of MS in patients of different age groups. MATERIALS AND METHODS: A prospective analysis of the data of neurological examination and results of magnetic resonance imaging of 100 patients of different age groups with relapsing-remitting MS, who received outpatient treatment in Kursk Regional Multidisciplinary Clinical Hospital, was conducted in the period of stable remission. RESULTS: The leading syndromes in patients with relapsing-remitting course of MS were cerebellar (78%) and pyramidal (70%) syndromes, besides, dysfunction of the cranial nerves (71%) was also observed. A quantitative parameter of explicitness of pelvic disorder syndrome predominated in middle-aged and elderly patients compared to young ones (p 0.001). Cognitive disorders were more often (14%) recorded in middle-aged and elderly patients (p 0.001). The use of glatiramer acetate permitted to reduce the degree of disability in young subjects (p 0.05); in patients of the middle age group, the most effective was a timely transition from interferon beta to ocrelizumab (p 0.05). The use of first-line MSDMDs (interferon-beta) in elderly patients demonstrated low effectiveness (p 0.05). CONCLUSION: In middle-aged and elderly patients with equal timing of MS onset, the neurological deficit is more expressed than in young ones. First-line pathogenetic therapy, in particular, glatiramer acetate, is more effective in young patients, while patients of middle age are recommended an early transition to second-line MSDMDs.