The authors discuss the detection of intracranial aneurysms (IA) by means of intravenous digital angiography (ivDSA) in (a)symptomatic first degree relatives of families in which two or more individuals have IA. ivDSA is an almost noninvasive and low-risk diagnostic procedure. Screening, by means of ivDSA, of two affected families is described. In family I which includes 7 members with proven IA, ivDSA has been carried out in 36 asymptomatic individuals: in one, a 6 X 15 mm aneurysm was found at the left posterior communicating artery (PCoA). In family II, including one member with a proven IA and another with a subarachnoid hemorrhage, ivDSA has been carried out in 4 members: one aneurysm with a diameter of 6 mm was found at the left PCoA. Conventional cerebral angiography (CCA) confirmed both IA's. Neurosurgical treatment followed. The advantages and disadvantages of ivDSA vs. CCA as elective screening procedure in such cases are discussed. Screening of asymptomatic first degree relatives of cases with familial IA by means of ivDSA is strongly advocated.