Objective:To determine interleukin (IL)-8 concentrations in ventricular cerebrospinal fluid from children with severe traumatic brain injury (TBI).Design:Prospective study.Setting:University children's hospital.Patients:Twenty-seven children hospitalized with severe TBI (Glasgow Coma Scale score ≤8), seven children with cerebrospinal fluid culture-positive bacterial meningitis, and twenty-four age-equivalent controls.Interventions:Placement of an intraventricular catheter and continuous drainage of cerebrospinal fluid.Measurements and Main Results:Median [range] cerebrospinal fluid IL-8 concentration in children with TBI (0-12 hrs) (4,452.5 [0-20,000] pg/mL) was markedly greater than that in controls (14.5 [0-250]) (p< .0001) and equivalent to concentrations in children with meningitis (5,300 [1,510-22,000] pg/mL) (p= .33). Cerebrospinal fluid IL-8 remained increased in children with severe TBI for up to 108 hrs after injury. Univariate logistic regression analysis demonstrated an association between cerebrospinal fluid IL-8 and child abuse (p= .07) and mortality (p= .01). Multivariate analysis demonstrated a strong, independent association between cerebrospinal fluid IL-8 and mortality (p= .01).Conclusions:The data are consistent with an acute inflammatory component of TBI in children and suggest an association between cerebrospinal fluid IL-8 and outcome after TBI. IL-8 may represent a potential target for anti-inflammatory therapy.