Aneurysm of the extracranial carotid artery is rare. 13 cases have been seen at the Vascular Diseases Research Unit, Department of Surgery, Zhongshan Hospital, Shanghai First Medical College, during the past 27 years. There were 3 internal carotid, 1 external carotid and 9 common carotid cases. The youngest patient was aged 5 years and the oldest 63; there were 8 males and 5 females. Two refused surgery, and the remaining 11 all had operations. Treatment consisted of aneurysm resection with ligation of the carotid artery in 5, primary anastomosis of the internal carotid artery in 2, silk prosthetic graft of the common carotid artery in 1, autogenous vein graft between the common and internal carotid arteries in 2 and wrapping in 1. There was 1 death and 1 instance of hemiplegia.