This paper describes the techniques and indications of the endovascular treatment of cerebral aneurysms. Although the treatment of choice for cerebral aneurysms is surgical, some lesions are inoperable, especially because of their localisation, their broad implantation with absence of a surgical neck or because of the critical clinical condition of the patient. For these cases, endovascular alternatives are available. For giant aneurysms of the vertebrobasilar system or large aneurysms of the carotid syphon, the endovascular treatment consists in the occlusion of the carrier vessel with endovascular balloons, after previous test occlusion. For small aneurysms, with difficult surgical access, like the basilar tip, the treatment is performed with electrocoils (GDC coils). These soft platinum coils are detached from the delivery wire by an electric current. It is the final purpose to entirely pack the aneurysm with coils. Finally, endovascular therapy can be of use in the treatment of vasospasms due to subarachnoid hemorrhage. In case of failure of medical therapy, balloon angioplasty or intra-arterial infusion of papaverine can elevate the vasospasm and prevent ischemic complications.