The intracranial arterial obstructions (narrowing or occlusion) found with intracranial tumors are rarely reported. Our 25 cases and those of the literature enable us to draw a statistical view of these facts. Meningiomas and gliomas are often concerned, and they principally involve the main arteries at the base of the brain. The practical interest in such pathology concerns: the risk of a fall in blood pressure during general anesthesia which may result in occlusion of a narrowed artery; the need to estimate the pathological state of one or several arteries passing by a tumor which must be removed; and the possibility of providing an extra-intracranial arterial bypass if necessary.