Traumatic intracranial aneurysms are rare, occurring in fewer than 1% of patients with cerebral aneurysms. They can occur following blunt or penetrating head trauma and are more common in the pediatric population. Traumatic aneurysms can be categorized histologically as true, false, or mixed, with false aneurysms being the most common. These aneurysms can present in a variety of ways, but are typically associated with an acute episode of delayed intracranial hemorrhage with an average time from initial trauma to aneurysm hemorrhage of approximately 21 days. The mortality rate for patients harboring these aneurysms may be as high as 50%. Prompt diagnosis based on arteriography and aggressive surgical management are associated with better outcome than conservative treatment. The authors describe a classification scheme for traumatic aneurysms based on their anatomical location and conclude that 1) post-traumatic aneurysm must be considered in patients with acute neurological deterioration following closed head injury; 2) they can occur following mild closed head injury; 3) they occur more commonly in children than in adults; and 4) surgical clipping and/or endovascular occlusion is the definitive treatment.