Object:The Korean Society of Cerebrovascular Surgery (KSCVS) reported the clinical and epidemiological characteristics,and outcome of the treatment of unruptured intracranial aneurysm (UIA) in 2006,using the nationwide multicenter survey in Korea.Methods:1696 cases were enrolled retrospectively over one year at 48 hospitals during that period.The following data were obtained from all patients:age,sex,presence of symptoms,locationand size of the aneurysm,treatment modality,presence of risk factors for stroke,and the postprocedural 30-day morbidity and mortality.