Familial intracranial aneurysm is rare. We have clipped two posterior circulation intracranial aneurysms in mother and son. Mother was 48 years old and presented with severe headache and drowsy mentality. A basilar artery bifurcation aneurysm was found on DSA(digital subtraction angiography) and successfully clipped with transsylvian pterional approach. Her son was 24-year-old and presented with seizure and drowsy mentality. An aneurysmal sac was found on the bifurcation of vertebral artery and posterior inferior cerebellar artery. We have clipped it successfully with far lateral suboccipital approach. The authors recommended the use of screening test, such as MRIand high resolution CT, on the group of patients with the characteristic features of familial intracranial aneurysm.