Objectives: The aim of this review paper is to investigate definition of immune reconstitution therapies and their mechanisms of action in the of multiple sclerosis treatment, to investigate the positioning of this therapy in the multiple sclerosis treatment algorithm and the advantages and disadvantages versus other existing therapies for a specific patient profile, by reviewing the available and relevant literature. Materials and methods: During the preparation of this review paper, a systematic and retrospective review of the relevant scientific and professional literature was made, emphasizing scientific articles with real world evidence and official guidelines of Croatian and international professional societies. During the research, key words and terms were used: MS treatment algorithm, immune reconstitution therapy in MS, induction therapy, escalation therapy, mechanism of action for immune reconstitution therapy (IRT) in MS, disease – modifying therapies (DMTs), guidelines for the treatment of multiple sclerosis. Results: Immune reconstitution therapy is one of the treatment options for multiple sclerosis, which mechanism of action is based on the reduction, repopulation, and reconstitution of the immune system, it is applied in a short time interval but achieves long-term efficacy. It is part of the escalation and induction treatment approach and can be administered sequentially. In addition to high efficacy, IRT is characterized by side effects such as delayed secondary autoimmunity, lymphopenia, and herpes zoster. According to the recommendations mentioned in this paper, the most benefit from the use of IRT in the treatment of MS will have patients who plan to become pregnant, patients who have an aggressive onset of the disease and want one of these therapies because their lifestyle demands it. Conclusion: Despite different mechanisms of action, IRT leads to qualitative and quantitative changes in the cells of the immune system. In the RRMS treatment algorithm, IRT is applied after disease progression despite treatment with one of the moderately effective DMTs (escalation approach) or immediately after the diagnosis of highly active disease with poor prognostic factors (induction approach). IRTs are a valuable highly effective therapeutic option for the MS treatment, they can be applied sequentially, it requires long term patient monitoring to reduce the risk of side effects. There are no efficacy and safety comparative studies, therefore data from daily clinical practice are extremely valuable and additional retrospective studies are needed to determine the similarities and differences between these therapies.