Cognitive impairment (CI), along with physical disability, is the most important clinical manifestation of multiple sclerosis MS and is detected in 40—70% of patients. Present in all types and forms of MS, it has a significant negative impact on social adaptation, ability to work and daily activity. Most often, CI includes problems with information processing speed, memory, visual-spatial perception and regulatory functions. At the moment, there is no single theory explaining the pathogenesis of CI. It is believed to be associated with lesions in white and gray matter, which are not visible on MRI, as well as neuroimmunological processes that disrupt synaptic transmission and plasticity. Therapeutic strategies in the treatment of CI are also ambiguous: there is evidence of minimal to moderate efficacy of drugs that alter the course of MS (PITMS), especially PITMS 2 lines, and symptomatic therapy. However, the greatest effect was noted in cognitive training. Screening for CI during routine examination of patients with MS becomes more convenient thanks to short scales and tools, which in turn allows specialists to carry out timely therapeutic and preventive measures. In our review, we tried to analyze updated data on the prevalence, structure, pathogenesis and therapy of CI in MS patients.