Objective To analyze the incidence of intracranial unruptured aneurysms in patients with internal carotid artery (ICA) stenosis (≥30％),the characteristics of aneurysms and risk factors in patients with ICA stenosis and intracranial aneurysm.Methods Clinical data of patients receiving digital subtraction angiography (DSA) at Peking University Third Hospital between January 2012 and June 2015 were retrospectively reviewed to identify patients with ICA stenosis and unruptured intracranial aneurysm.Results Among 247 patients with ICA stenosis,16 patients (6.5％) with intracranial unruptured aneurysms were found including 7 females and 9 males with age from 47 to 83 years old.The severity of ICA stenosis in aneurysm group was (85.3± 13.2)％,whereas it was (77.7± 17.9)％ in non-aneurysm group.The incidence of aneurysms in male patients with ICA stenosis was 4.5％ (9/202),and 15.6％(7/45) in female patients (P＜ 0.05).The incidence of aneurysms in patients with only in cervical segment (C 1 segment) of ICA was 4.4％ (10/226),whereas that of other segment was 28.6％(6/21) (P＜0.05).Logistic multivariate regression analysis showed that gender and stenosis location were independent risk factors of aneurysms in patients with ICA stenosis.Conclusions In patients with ICA stenosis,the incidence of aneurysm is much higher than that in general population.Intracranial aneurysms are more likely to occur in women and patients with ICA stenosis other than C 1 segment.