Adherence to therapy largely determines the success of treatment interventions: low levels of adherence are associated with reduced treatment effectiveness. For many chronic diseases, the level of adherence to treatment is about 50% or less, which confirms the relevance of this topic and requires its research. The high costs of treatment, the need for long-term continuous use of drugs and the special socio-economic significance of a disease such as multiple sclerosis (MS) determine the importance of maintaining a high level of adherence to its treatment. An analysis of literature data on the concept of treatment adherence, methods of its definition and influencing factors was carried out, the values of the level of adherence in the treatment of MS, as well as measures to maintain it during the COVID-19 pandemic were considered. Increasing awareness of healthcare professionals about the problem of treatment adherence and ways to improve it helps to improve the efficiency of managing patients with MS. The paper considers the primary stage of the strategy to improve treatment adherence among patients with MS, namely the formation of expanded knowledge of the problem by specialists of a multidisciplinary team involved in the diagnosis and treatment of patients with MS.