Hypoalbuminemia and anemia are frequent among in patients with traumatic brain injury (TBI). We assess whether serum albumin and hemoglobin at admission can predict outcome in children with moderate to severe TBI.This retrospective study was conducted in a tertiary pediatric hospital between May 2012 and Jun 2018 included children with an admission Glasgow Coma Scale of ≤13.A total of 213 patients were included of whom 45 died in hospital. Multivariate logistic regression showed that hypoalbuminemia (serum albumin <30 g/L) was independently associated with mortality (adjusted odds ratio [OR] = 3.059; 95% confidence interval [CI]: 1.118-8.371; P = .030) in children with moderate to severe TBI, while anemia (hemoglobin <90 g/L) was not independently associated with mortality (adjusted OR = 1.742; 95% CI: 0.617-4.916; P = .295). Serum albumin was significantly superior to hemoglobin (area under the curve [AUC] 0.738 vs AUC 0.689, P < .05) under receiver operating characteristic curve analysis. Hypoalbuminemia was also associated with reduced 14-day ventilation-free days, 14-day intensive care unit (ICU)-free days, and 28-day hospital-free days.Serum albumin at admission was superior to hemoglobin in predicting the mortality in children with moderate to severe TBI and also associated with reduced ventilator-free, ICU-free, and hospital-free days.