A 45-year-old male was admitted for evaluation of left facial pain of 11-years' duration. Fifteen years prior to admission, he had had an episode of subarachnoid hemorrhage. Neurological examination revealed no definite abnormalities except for trigeminal neuralgia involving the left second division of the nerve. Computed tomography scan showed an irregular enhanced lesion involving the lateral aspect of the left cerebellar hemisphere. Vertebral angiograms revealed an arteriovenous malformation (AVM) fed by both the dilated left anterior inferior cerebellar (AICA) and superior cerebellar arteries (SCA) and draining into the superior petrosal and transverse sinuses via three enlarged draining veins. A saccular aneurysm was incidentally visualized at the proximal portion of the dilated AICA. The AVM was successfully extirpated through the left retromastoid craniectomy. The trigeminal nerve was directly compressed both rostrally and caudally at its entry zone by two dilated feeding arteries of the SCA and the AICA. The aneurysm was simultaneously obliterated. The postoperative course was uneventful, and the excruciating facial pain completely subsided. Postoperative angiograms confirmed disappearance of both the AVM and the aneurysm. Posterior fossa AVMs causing trigeminal neuralgia in the literature are reviewed, and the association of the AVM and the aneurysm in the posterior fossa is also discussed.