The indications for treating carotid artery stenosis are related to the symptomatic nature of the lesion and the degree of stenosis. Duplex sonography is adequate for screening. While some groups believe that Duplex US alone or in combination with transcranial Doppler imaging may be sufficient for presurgical evaluation, it often is recommended to complete the evaluation with either MRA or CTA. Both techniques are advantageous since they allow evaluation of the cervical and intracranial arteries as well as cerebral parenchyma hence providing valuable information prior to definitive management. Catheter angiography remains indicated in patients with multi-vessel disease and ischemic cardiomyopathy, when results at non-invasive evaluation are discordant or in an emergency setting. Duplex US is used for routine follow-up of non-surgical lesions and after endarterectomy. Transcranial Doppler as well as advances in MRA and CTA techniques will be reviewed. Even though the treatment of atherosclerotic carotid artery stenoses remains primarily surgical, specific considerations related to angioplasty will be reviewed. Finally, diseases of the intracranial carotid artery and non-atherosclerotic diseases (dissection...) will also be discussed.