The ideal treatment of children with head trauma would include prevention of posttraumatic seizures. Ninety-two of 937 children with head injuries (9.8%) experienced posttraumatic seizures. In 94.5% of these patients (87 of 92), seizures developed within the first 24 hours after injury. Three children convulsed between 24 hours and 7 days, but only 2 children developed seizures after the 1st week. Factors found to influence the likelihood of seizures included severe head injury (GCS, 3 to 8), diffuse cerebral edema, and acute subdural hematoma (P less than 0.001). Seizures occurred in 35% of severely head-injured children compared to 5.1% with minor head injury (P less than 0.001). A less significant correlation (P less than 0.1) was noted between seizures and open, depressed skull fractures. We found no significant correlation between seizure occurrence and numerous other factors including age, sex, fracture location and type (other than open, depressed fractures), parenchymal injuries, fixed neurological deficits, and cranial operation. Based on our observations, we recommend the prophylactic use of anticonvulsants in children at higher risk for posttraumatic seizures: those with diffuse cerebral edema, acute subdural hematoma, open, depressed skull fracture with parenchymal damage, or severe head injury (GCS less than or equal to 8).