Purpose:Severe head traumas in the childhood age group has an important place in terms of mortality and morbidity among all traumas. Our aim in this study is to consider the relationship between the severity of severe head trauma and arterial blood gas (ABG) parameter levels in children.Methods:In our study, patients with head trauma, intubation and Glascow Coma Score (GCS) ≤ 8 were retrospectively analyzed. Showing homogeneous distribution; Independent sample T test was used for pH, PCO2 and base extract (BE) parameters, and Mann Whitney U test was used for PO2 and lactate parameters not showing homogeneous distribution. ROC analysis was done.Results:Of the 48 patients included in the study, 17 died while lying in the intensive care unit. There was no statistical difference when looking at the relationship between age, gender, surgical methods and mortality of the patients (p> 0.05). The relationship of patients with acidosis, hypercapnia and hyperlactatemia in ABG with mortality was statistically significant (p˂0.05). No statistically significant difference was found between surviving and deceased in ABG of patients regarding BE and hypoxia (p= 0.075; 0.175). there was a statistically significant difference between the mean values of PCO2 and lactate which are among the quantitative values and those who survived and died (p <0.05).Conclusion: Acidosis, the presence hypercapnia and hyperlactatemia were found to be associated with mortality in children with severe head trauma in ABG analysis. This study shows that PCO2 and lactate levels in ABG can be a biomarker in determining the prognosis in pediatric patients with traumatic brain injury (TBI).