The Guglielmi detachable coil (GDC) is an important tool for the treatment of ruptured intracranial aneuryms by an endovascular approach. This new device may be introduced under fluoroscopy into the aneurysmal sac through a microcatheter. When the coil is judged well positioned, it can be detached with accuracy by electrolytic breakdown. The procedure is completed when a dense coil packing is obtained. When vasospasm is present, papaverin infusion or angioplasty may be used by the endovascular approach as well. Best results are achieved in cases of small aneurysm with small neck. The morbidity and mortality rates in the first 200 patients treated by GDC for a ruptured intracranial aneurysm were 4% and 1.5%, respectively. Complications are generally related to rupture of the malformation by the endovascular device or to thromboembolic events. Despite these promising results, further studies using larger numbers of patients are required to determine the exact role of these procedures in patient care.