True aneurysm of the carotid artery is relatively rare in comparison with the total number of aneurysms of the arterial system. The threat of rupture and embolization from mural thrombi are indications for treatment even though no symptoms may be present. Resection of the aneurysm and restoration of arterial continuity is the treatment of choice. A case of aneurysm of the Lt. common carotid artery of a 21 year-old male patient is presented. The confirmatory diagnosis was made by left carotid angiogram, and the aneurysmectomy & reconstruction with woven dacron vascular prosthesis was done, while cerebral circulation was maintained by internal shunt. [KTCS 1981;1:63-66]