Objective. To study an impact of cytoflavin on the functional state of erythrocytes in patients with Charcot — Marie — Toota disease (CMTD). Material and methods. Thirty patients with CMTD were examined. The main group (n=17) received cytoflavin along with basic therapy (intravenously dropwise 10 ml per 200 ml of 5% glucose solution for 10 days). The comparison group (n=13) received only basic therapy. Functional parameters of erythrocytes, including electrophoretic mobility of erythrocytes (EFME), concentration of malonic dialdehyde (MDA), content of ATP and 2.3-DPG in erythrocytes, were evaluated. The level of physiological norm of the studied parameters was determined in 20 healthy people (the control group). To assess clinical symptoms, the MFI-20 scale and a 20 meter walking distance were used. Results and conclusion. There was a decrease in EFME and concentrations of ATP, 2.3 DFG and an increase in MDA concentration in the main group compared to the control group. After treatment with cytoflavin, there was an increase in the content of ATP, 2.3 DFG and EFME and a decrease in the concentration of MDA. The similar but less pronounced changes were observed in the comparison group. At the same time, the content of 2,3 DPG and the concentration of MDA did not reach the level of the physiological norm. The changes in functional indicators of erythrocytes were associated with clinical indicators. A significant decrease in the severity of asthenia according to the MFI-20 scale, an increase in walking speed, a decrease in the average walking time by 20 seconds (by 5 seconds in the comparison group) were observed in the main group. The results make it possible to classify the use of cytoflavin in CMTD as a method of pathogenetic therapy.