A 44-year-old right-handed man was hospitalized because of a subarachnoid hemorrhage. He was drowsy on admission and exhibited a left partial third nerve palsy, right hemiparesis, and selective motor aphasia. A large subcortical arteriovenous malformation involving the left frontal lobe was demonstrated by angiography. The malformation filled from either carotid system and from the vertebrobasilar system as well. In addition, there were two bilaterally symmetrical (mirror) aneurysms of each internal carotid artery. Computed axial tomography revealed a left intratemporal-intraventricular hematoma. Deterioration of the patient's clinical condition occurred a few days after admission. Improvement was obtained after removal of the hematoma at a left subtemporal craniectomy, at which time the ruptured aneurysm arising from the left internal carotid artery was clipped. Sixteen months later, the intact aneurysm of the right internal carotid artery was clipped, and the arteriovenous malformation was radically excised through a bifrontal (Pool) craniotomy with microsurgical technique and with the aid of intraoperative angiography. The patient remained with a fixed neurological deficit, as observed preoperatively.