Post-traumatic seizures (PTS) can be a serious complication of head injury, because they can cause secondary brain damage through increased metabolic requirements, raised intracranial pressure, cerebral hypoxia, and/or excessive release of neurotransmitters. In children, early PTS are more frequent than late ones. In this retrospective study we conducted an epidemiological analysis and tried to identify potential risk factors for the onset of early PTS in children hospitalized for head injury in our Paediatric Intensive Care Unit. The severity of injury was assessed using the Glasgow Coma Scale (GCS), while the outcome of traumatized children was defined using the Glasgow Outcome Score (GOS). Early PTS were diagnosed in 15 out of the 125 children hospitalized (12%). Most of the children (73.3%), developed seizures within 24 h of the trauma (immediate PTS). Among the risk factors, a very important role was played by the severity of the injury; in fact, the incidence of early PTS among patients with GCS < or = 8 was ten times greater than that among children with GCS 13-15. Other risk factors that significantly influenced the onset of early PTS, were age (60% of children with early PTS were less than 3 years old) and severe cerebral edema. Overall, children with early PTS had a worse outcome than the other patients. In fact, 53% had a GOS of < or = 3 compared to 19.1% of those without early PTS (P<001). In particular, considering children with severe head injury, 80% of those with early PTS had a GOS of < or = 3, compared to 41% of those without early PTS (P<0.05). In conclusion, PTS can be a serious complication of head injury in children, because they can worsen secondary brain damage. Appropriate management of head-trauma patients must include suitable and immediate prophylaxis with anti-epileptic drugs.