Unruptured intracranial aneurysms occur in 1-3 % of the general population, and the risk of rupture is generally considered to be low. However, patients with multiple aneurysms and familial predisposition carry a particular risk of subarachnoid hemorrhage (SAH). A 54-year-old hypertensive man underwent screening with a head CT angiography (CTA) because of his comorbidities. CTA revealed multiple bilateral aneurysms around the circle of Willis. At first surgery, seven aneurysms were clipped (BA, ACOM, ICA ×2, and MCA ×3), two of which were detected intraoperatively only. During the second surgery, another three aneurysms were surgically clipped (PCOM and MCA ×2), one of which was detected intraoperatively. Follow-up angiography revealed another two aneurysms. A PCOM aneurysm was treated by coil embolization and a VA aneurysm clipped surgically during a third admission. The patient made an uneventful recovery. However, 4 months after his second surgery, his daughter underwent surgical clipping of a right-sided ICA aneurysm. This case report highlights both the importance of screening of high risk patients with family history of SAH, as well as its limitations, as our patient developed two de novo aneurysms during 6-month follow-up and CTA preoperatively missed three small aneurysms.