The impact of sub-clinical seizures on outcomes and management of adult head injury have been studied extensively. In this study, children with moderate or severe TBI (GCS 3-12), admitted to Children’s Hospital of Colorado, underwent at least 48 hours of continuous EEG (cEEG) monitoring. The mean age of these patients was 4.8 years, and the most common mechanism of injury was abusive head trauma (AHT, 45%). Ninety-three percent received prophylactic anticonvulsant treatment per institutional protocol. Seizures were identified in 30% of patients. Of these, many had seizures apparent only on EEG, without clinical manifestation: 40% only subclinical seizures, 93% at least one subclinical seizure. Age less than 2.4 years and AHT were strongly associated with seizures. While there was no correlation between seizures and discharge disposition, patients with seizures had significantly longer hospitalization. This prospective study demonstrates a role for cEEG to identify early seizures in a significant proportion of children with moderate to severe TBI. Routine use of cEEG may be warranted, especially in children younger than 2.4y and those with abusive head trauma.