Abstract： Objective To study the efficacy and safety of intra-aneurysmal Onyx embolization of intracranial aneurysms of the distal end of posterior circulation with parent artery preservation.Methods Twelve consecutive patients harboring 12 intracranial aneurysms of the distal end ofposterior circulation underwent intra-aneurysmal Onyx embolization.The locations of the aneurysms were as following:posterior cerebral artery (PCA) in 2 patients,superior cerebellar artery (SCA) in 3 patients,anterior inferior cerebellar artery (AICA) in 2 patients,and posterior inferior cerebellar artery (PICA) in 5 patients.The technical feasibility of the procedure,procedure-related complications,angiographic results,and clinical outcomes were evaluated.Results In every case,endovascular treatment was achieved.Immediate angiography demonstrated that all of 12 aneurysms were completely occluded,with parent arlery preservation in 11 of them.Procedure-related complication occurred in one patient with transient neurological sequelae.There was norebleeding or recanalization of the aneurysms during follow-up duration.Conclusions The intra-aneurysmal Onyx embolization is helpful in the treatment of intracranial aneurysms of the distal end of poslerior circulation in which selective occlusion of the aneurysmal sac with coils or open clipping cannot be achieved.