To determine the incidence and nature of cranial nerve damage in connection with carotid artery surgery, 139 patients were studied before and after 162 operations. Nerve damage was detected in association with 19.8% of the operations. The hypoglossal nerve was most commonly affected. The injuries were of benign character and usually resolved within 4 to 6 weeks. Apart from damage to the great auricular nerve, all lesions resolved within 5 months. The incidence of nerve disturbance was greater than that found in a retrospective study from the same hospital. Gentleness of technique is important in carotid artery surgery, in order to avoid nerve damage.