We report a patient with combined thrombophilia--protein C deficiency and mild hyperhomocysteinemia with total spontaneous thrombosis of a basilar tip aneurysm after subarachnoid hemorrhage, without neurological deficit. At admission, the patient had headache, drowsiness, and nausea, with no neurological deficit. Computed tomography (CT) did not show the presence of subarachnoid blood, and magnetic resonance examination revealed discrete remains of a subarachnoid hemorrhage in projections of temporal, frontal and occipital lobes, with no vascular abnormalities. Initial angiography showed a small basilar tip aneurysm and the patient was scheduled for endovascular treatment. A second angiography, performed before the planned endovascular treatment, did not show the aneurysm and complete thrombosis was suspected. A follow-up angiogram, 6 months after this event, showed preserved posterior cerebral circulation with no aneurysm present. The patient was discharged in good condition, without neurological deterioration. We did not find any previous reports of similar conditions.