Three patients presented with giant aneurysms of the intracranial internal carotid artery that became symptomatic with expanding mass effects 4-10 years after severe head trauma accompanied by skull base injuries at the site of aneurysm formation. These aneurysms are therefore considered to be late manifestations of traumatic vessel disruption. Posttraumatic aneurysm growth was documented in one case of a supraclinoidal aneurysm. One intracavernous aneurysm was combined with a traumatic carotid-cavernous sinus fistula. Although the origin of intracranial aneurysms is usually considered to be traumatic only within a period of weeks or months after head injuries, giant aneurysms of the intracranial internal carotid may represent late complications of trauma in a number of cases.