In addition to progressive endocrine dysfunction and progressive visual loss, pituitary neoplasms may announce their presence by the more catastrophic alternative of spontaneous tumor infarction. In two patients reported, illness due to the spontaneous infarction of pituitary tumors was heralded by sudden onset of focal headache associated with diplopia. Stupor, confusion, and evidence of increased intracranial pressure occurred without subarachnoid hemorrhage or massive extrasellar extension of tumor. One patient developed inappropriate antidiuretic hormone secretion with spontaneous infarction in a large but clinically silent chromophobe adenoma. In both patients, skull x-rays suggested a long-standing intrasellar mass. Both undewent prompt treatment with endocrinologic replacement therapy and subsequent successful transsphenoidal removal of voluminous, infarcted, pituitary masses.