A 27-year-old man was admitted with symptoms of hypertension and headache. His soft palate and uvula were deviated to the right. The left side of his tongue was atrophic with fasciculation. Plasma renin activity, plasma angiotensin-I and aldosteron levels were elevated. Renal arteriography revealed membranous-stenosis with poststenotic dilation at the mid and peripheral portion of the renal artery, which was consistent with the findings of fibromus-cular dysplasia (FMD). Large aneurysm at the bifucation of the vertebral artery to postero-inferior cerebellar artery was observed by cerebral arteriography. The patient was treated with medication for renal hypertension. Percutaneous embolization of the aneurysm was performed. In conclusion, the present case had a giant cerebral aneurysm, located at a rare portion and was diagnosed before its rupture. Examination of the cerebral artery was essential in renal FMD.