A 55-year-old male patient presented with a giant olfactory groove meningioma supplied by both ophthalmic arteries. The tumor was debulked through a bifrontal craniotomy, but the surgery was discontinued because of extensive blood loss. During a second operation, the dura of the frontal base was dissected extradurally before the tumor was removed. The meningeal blood supply was occluded with bipolar coagulation of the epidural meningeal vessels around the crista galli. The highly vascular tumor then was totally removed with considerably less blood loss. The patient's postoperative course was uneventful. Because the ophthalmic artery cannot be embolized preoperatively, the direct extradural approach to the skull base to devascularize the blood supply around the olfactory groove may reduce blood loss and facilitate resection.