Objective — to study the content of biomarkers of diagnostic and prognostic value in the assessment of traumatic brain injury (TBI) severity in children. Material and methods. Authors determined the levels of glial protein S100B, neuronspecific enolase (NSE), autoantibodies (aAb) to glutamate receptors and natural autoantibodies (nAb) to S100B and brain-derived neurotrophic factor (BDNF) in serum/plasma of children with different outcomes of TBI. All parameters were analyzed in the 1—3rd, 7—8th, 14—15th and 20—23rd days after TBI, and, in some cases of severe brain injury and long stay patients in hospital, in 11—12 months after TBI. The severity and outcome of TBI were assessed according the Glasgow coma scale (GCS) and the Glasgow outcome scale (GOS), respectively. Results and conclusion. The content of NSE and S100B increased immediately after TBI regardless of TBI severity, but in cases with favorable outcome it dropped to a normal level in the first 3 days. The maximum levels of S100B protein and NSE were observed in children with fatal TBI, and higher values were observed throughout the post-traumatic period. The low levels of aAb to NR2-subtype of glutamate receptors that were similar to controls and the high level of nAb to S100B in the first days after severe TBI indicate the failure of compensatory-adaptive immunological mechanisms and the high permeability of the brain-blood barrier, which were poor prognostic signs for children with severe TBI. Mild and severe TBI with full recovery were accompanied by higher values of ВDNF in the 1st day followed by a decline to the 3rd day. The level of BDNF in the 1st day of TBI was the lowest and subsequently continued to decline in patients with severe TBI with fatal outcome.