We report four pediatric traumatic intracranial aneurysms occurring before the age of 10 years. Two of these aneurysms were the result of closed head injury. The remaining two were iatrogenic aneurysms which occurred in unusual circumstances. These four children represent 33% of the pediatric intracranial aneurysms seen at the Children's Hospital of Eastern Ontario from 1974 to 1992. Diagnosis of traumatic intracranial aneurysms requires a high index of suspicion: any head-injured or postoperative child who experiences delayed neurologic deterioration, or who fails to improve as expected following treatment, should promptly undergo diagnostic intracranial imaging. Documented subarachnoid hemorrhage, intracerebral or intraventricular hemorrhage, or subdural haematoma in this clinical setting should be further investigated by cerebral angiography to exclude a traumatic aneurysm or other vascular lesion. Traumatic aneurysms typically arise at the skull base or from distal anterior or middle cerebral arteries or branches consequent to direct mural injury or to acceleration-induced shear. Reported traumatic aneurysms account for 14%-39% of all pediatric aneurysms. Iatrogenic aneurysms also occur with unexpected frequency during childhood and adolescence. Pediatric traumatic cerebral aneurysms may present early or late. Most present early with intracranial hemorrhage. Late presentation occurs infrequently, typically as an aneurysmal mass. Once diagnosed, these aneurysms should be promptly treated by craniotomy employing routine microsurgical techniques, or in some cases, by endovascular detachable balloon techniques. Delay in operative treatment entails significant risks of repeated hemorrhage and death. Outcome in these children is primarily determined by the extent of traumatic cerebral injury and the preoperative clinical status. The latter directly depends upon diagnosis of the aneurysm prior to either initial or repeated hemorrhage.