We have studied the indexes of albumin’s value and IgG immunoglobulin in the blood serum and in the cerebrospinal fl uid in order to determine the peculiarities of functioning of bloodbrain barrier (BBB) in 280 patients within diff erent courses of multiple sclerosis. We assessed the value of albumin and IgG immunoglobulin considering the course of the disease, the stage of process’s activity (at stages of progression and stabilization), the gender-sensitive issue, the duration of the disease, the severity of neurological defi cit according to the EDSS scale. We have showed that the degree of BBB permeability predominantly related to the stage of the process’s activity. The BBB permeability was much less aff ected by the course of the disease. Such indicators as gender, the duration of the disease and the severity of neurological defi cit according to the EDSS scale actually do not have any infl uence.