Blunt injury of the internal carotid artery is rare and easily overlooked. The injury should be considered in a conscious patient with dense neurological deficit after blunt trauma to the head and neck. The diagnosis was established in 17 patients (9 men, 8 women) by arteriography. There was a median delay of 19 hours in the onset of neurologic deficit in 15 patients. Follow up arteriography was obtained in 16 of the 17 patients with a median interval of three months between arteriograms. On repeat arteriography, the internal carotid artery was patent in three of the nine patients with internal carotid arteries occluded on initial arteriography. Surgical repair was attempted in six patients. No significant difference in long term neurological deficit occurred between patients treated conservatively and those treated operatively. Of the 15 patients with hemiparesis on presentation, eight made a complete recovery and six improved. This study supports nonoperative management for blunt injuries of the internal carotid artery.