AIMTo evaluate efficacy and safety of biosimilars of interferon beta-1b (Infibeta) in patients aged 14 to 17 years.MATERIAL AND METHODSInterferon beta 1b (Infibeta) was appointed 9 children and adolescents (4 boys and 5 girls) between the ages of 14 to 17 years (mean age of onset of therapy 16.22±1.09).RESULTSIn the course of therapy there was a significant decrease in the annualrelapse rate (ARR) to 0.33±0.5 (from 0 to 1, r≤0,0001) and the of regression of neurological deficit on the EDSS scale up to ±1.94±0.68 (1.5 to 3, p≤0.05). No cases of cancellation was not recorded due to poor tolerability or inefficiency.CONCLUSIONAlthough numerically small so far, but quite successful results on the use of Russian interferon beta-1b biosimilar (Infibeta) in children, we can recommend this treatment as sufficiently safe and effective.