Surgical access to aneurysms of the basilar trunk and vertebrobasilar junction is hampered by their direct proximity of these lesions to highly vulnerable neural structures like the brain stem and cranial nerves, as well by the bony structure of the petrous bone blocking the direct surgical approach to these aneurysms. Only recently lateral approaches directed through parts of the petrous bone have been reported for surgery of basilar trunk and vertebrobasilar junction aneurysms like the anterior transpetrosal, the retrolabyrinthine transsigmoid, as well as the combined supra-infratentorial posterior transpetrosal approach. As experience in the use of this approach is limited in the neurosurgical literature we present our surgical experiences in 11 patients with basilar trunk and vertebrobasilar junction aneurysms, operated on using the supra-infratentorial posterior transpetrosal approach. In 10 patients, including one patient with a giant partially thrombosed basilar trunk aneurysm, direct clipping of the aneurysm via the transpetrosal route was possible. In one patient with a giant vertebrobasilar junction aneurysm, the completely calcified aneurysm sac was resected after occlusion of the vertebral artery. Of the whole series, one patient died and in three patients postoperative accentuation of preexisting cranial nerve deficits occurred. Except transient cerebrospinal fluid leak in two patients, the postoperative course was uneventful in the remaining patients. Postoperative angiography demonstrated complete aneurysm clipping in ten patients and relief of preoperative brain stem compression in the patient with the giant vertebrobasilar junction aneurysm. It is concluded, that the supra-infratentorial posterior transpetrosal approach allows excellent access to the basilar artery trunk and vertebrobasilar junction and can be considered the approach of choice to selected aneurysms located in this area.