BACKGROUND: To compare admission lactate and base deficit (BD), which physiologically reflect early hemorrhagic shock, as outcome predictors of pediatric trauma. METHODS: We reviewed the data of children with trauma who visited a Korean academic hospital from 2010 through 2018. Admission lactate and BD were compared between children with and without primary outcomes. The outcomes included in-hospital mortality, early (≤24 h) transfusion, and early surgical interventions for the torso or major vessels. Subsequently, performances of lactate and BD in predicting the outcomes were compared using receiver operating characteristic curves. Logistic regressions were conducted to identify the independent associations of the two markers with each outcome. RESULTS: Of the 545 enrolled children, the mortality, transfusion, and surgical interventions occurred in 7.0%, 43.5%, and 14.9%, respectively. Cutoffs of lactate and BD for each outcome were as follows: mortality, 5.1 and 6.7 mmol/L; transfusion, 3.2 and 4.9 mmol/L; and surgical interventions, 2.9 and 5.2 mmol/L, respectively. No significant differences were found in the areas under the curve for each outcome. Of the two markers, a lactate of >5.1 mmol/L was associated with mortality (adjusted odds ratio, 6.43; 95% confidence interval, 2.61-15.84). A lactate of >3.2 mmol/L (2.82; 1.65-4.83) and a BD of >4.9 mmol/L (2.32; 1.32-4.10) were associated with transfusion, while only a BD of >5.2 mmol/L (2.17; 1.26-3.75) was done with surgical interventions. CONCLUSIONS: In pediatric trauma, lactate is more strongly associated with mortality. In contrast, BD may have a marginally stronger association with the need for hemorrhage-related procedures.