Two patients with complex aneurysms of the vertebrobasilar system were treated using platinum coils. During these sessions, 22 coils were placed in a basilar tip aneurysm in a 48-year-old woman. Almost total occlusion of the lumen was achieved, excepted in the area from which the right posterior cerebral artery arose. A large fusiform vertebral artery aneurysm in a 6-year-old boy was treated using 16 coils, which partially occluded the lumen at initial embolization. Follow-up angiography 2 weeks later revealed almost complete occlusion of the lumen with preservation of the vertebral artery. Our experience indicates that coil embolization of complex intracranial aneurysms is an acceptable treatment alternative to surgery or to a detachable balloon.