A 52-year-old woman was admitted to our hospital presenting with subarachnoid hemorrhage, left ophthalmoplegia, and right hemiparesis. Previous symptoms and signs suggested the presence of panhypopituitarism. A giant intracranial aneurysm of the internal carotid artery, diagnosed by magnetic resonance imaging, showed the characteristic flow void phenomenon with black appearance. Analysis of endocrine function disclosed panhypopituitarism and hyperprolactinemia. After proximal balloon occlusion of the aneurysm, diabetes insipidus developed. Pituitary function reassessed 6 months after initial admission confirmed anterior and posterior hypopituitarism and hyperprolactinemia. Possible mechanisms are discussed. A review of the literature on pituitary dysfunction caused by carotid artery aneurysms discloses that the pituitary-gonadal axis is the most frequently involved (67.5% of cases), followed by the pituitary-adrenal axis (48.6%) and the pituitary-thyroid axis (40.5%). These frequencies are very similar to those described in other types of hypopituitarism.