Hyperglycemia among adult trauma patients with head injuries is a recognized phenomenon which has been shown to be associated with a poor prognosis when it takes the form of nonketotic hyperosmolar hyperglycemia. It is not known to what extent a similar phenomenon occurs in pediatric patients, although it is known that a child's physiologic response to injury, particularly to neurologic injury, is often different than an adult's. This study was undertaken to characterize the hyperglycemic response of children with closed head injury compared to children with a non-head injury, and to measure the extent to which the presence of hyperglycemia is associated with a poor outcome among children with severe head injury. Records for all children ages 2 to 12 years admitted to a major regional trauma center with closed head injury over a 6-year period were compared to the records of a control group of children hospitalized for a non-head injury. The hyperglycemic response was more common among those with head trauma, occurring in 40% compared to 5% of the controls (p<0.001); however, the level of hyperglycemia could not be associated with any indicator of outcome. The entity known as nonketotic hyperosmolar hyperglycemia did not occur in any of these patients. Apparently, the hyperglycemia associated with closed head injury in children is transient, does not need to be treated with insulin therapy, and in contrast to what has been demonstrated in adult trauma patients, does not predict patient outcome.