A 58-year-old female was admitted unconscious to a local hospital. Computed tomography demonstrated subarachnoid hemorrhage. Cerebral angiography revealed evidence of moyamoya disease and a saccular aneurysm at the tip of the basilar artery. The patient was transferred to our hospital for embolization of the basilar tip aneurysm. Endovascular embolization was performed using Guglielmi detachable coils (GDCs), and the aneurysm was completely occluded with preservation of the parent artery. No change in the patient’s neurological status was seen during and after the procedure. Endovascular treatment using GDCs appears to be particularly suitable for ruptured cerebral saccular aneurysms in patients with moyamoya disease.