Radiation angiopathy is a well-known complication accompanying irradiation. But the majority of effected vessels are small vessels. Cases of intracranial major arteries being effected are not so numerous. We report the case of a 47-year-old female patient. The removal of pituitary adenoma was carried out on her in 1982. After that, 4500rad irradiation was performed. It was about six years after irradiation that the first angiography was made. Right MCA occlusion, multiple stenosis of both ACAs and Moya-Moya like vessels were discovered. On admission light paresis on her left lower extremity was recognized and hyperlipidemia was noted. It was interesting that the multiple stenosis was found in an area outside the irradiation field. MCA-STA anastomosis was performed and the prognosis was good. The authors described this case and reviewed the pertinent literature.