We studied by magnetic resonance angiography and cerebral angiography 41 patients with 55 aneurysms confirmed by surgery. The MR angio detected 52 aneurysms with sensibility of 94.5% and the cerebral angiography detected 53 aneurysms with sensibility of 96.3%. For being non invasive, more quickly and less expensive MR angio may substitute vascular angiography in the diagnosis of intracranial aneurysms and prognosis of the subarachnoid hemorrhage