Endovascular therapy for cerebral aneurysms has been possible since the advent of Guglielmi detachable coils. The International Subarachnoid Aneurysm Trial (ISAT) showed that the 1-year outcome of endovascular coiling for ruptured aneurysms was significantly better than that of neurosurgical clipping. After the ISAT study, remarkably high numbers of aneurysms have been treated using coils across the world. Digital subtraction angiography (DSA) system and its road map function are also essential for endovascular therapy. Three-dimensional DSA is helpful in understanding the anatomy of an aneurysm that has to be treated and determining the working angle for coiling. The biplane system is also useful for embolization. Many kinds of coils such as three-dimensional shaped coils and stretch-resistant coils have been invented. These coils, in combination with balloon-or stent-assisted techniques, enable the treatment of difficult aneurysms such as those with wide necks. Bioactive coils allow the healing of aneurysm by promoting tissue reaction. However, it is difficult to cure very large and giant aneurysms even with the new coils. Hence flow-diverting stents and Onyx are being clinically tested for the treatment of such cases.