Extra-cranial carotid artery aneurysms (ECAA) are uncommon and represent a therapeutic challenge for clinicians. An ECAA is generally defined as a dilation of the internal carotid artery (ICA) or common carotid artery (CCA) greater than 150% of the diameter of the normal healthy artery. The presence of an ECAA is usually found by coincidence in asymptomatic patients. Symptomatic patient may present with neurological dysfunction or symptoms of local compression. The initial diagnosis of ECAA is often by echo/duplex ultrasound imaging. However, computerized tomographic angiography (CTA), with 3-dimensional reconstruction of the images (3D) can provide additional and valuable information, especially when considering surgical exclusion of the aneurysm. Recently, vessel wall imaging using contrast enhanced magnetic resonance with gadolinium administration was explored, which could potentially provide valuable information regarding aneurysm wall changes during clinical follow up. Location and accessibility of an ECAA is key information when considering the appropriate treatment. With the lack of evidence based treatment guidelines, a conservative approach with or without medicinal treatment is currently the standard of care for asymptomatic non-growing ECAA. Open surgical repair has for long been the accepted treatment for patients with a growing aneurysms or aneurysm related symptoms. Endovascular interventions are increasingly applied, especially when surgical intervention is considered too risky or not possible due to patient comorbidities or anatomical restrictions. Data on the natural course, immediate and long-term results of surgical or endovascular therapy is scarce. Thus, there is a clear need for an international collaboration collecting data of ECAA within a registry.