The authors report a case of a basilar artery aneurysm approached by the transsylvian route; the aneurysm was successfully clipped through the space distal to the carotid bifurcation and between the frontal and temporal lobes. This approach is useful when the internal carotid artery is short, sclerotic, and difficult to mobilize. Special care should be taken when retracting perforating arteries and the posterior communicating artery.