Primary atherosclerotic aneurysms of the carotid artery are extremely rare. Most cases are due to atherosclerotic disease, pseudoaneurysms secondary to neck trauma or previous surgery and mycotic aneurysms. Vascular surgeons will very likely encounter only a few of these aneurysms in their professional life as surgeons. These aneurysms pose a significant risk to the patient, due to embolisation of the thrombus, neurological complications, compression of adjacent neck structures and rupture from infection and previous surgery. The following case report describes the presentation and surgical treatment of a spontaneously ruptured gigantic common carotid artery aneurysm.