Deficiencies of corticotrophin (ACTH), growth hormone, and prolactin were documented in a woman with diabetes mellitus and Sheehan's syndrome. The patient's ACTH deficit appeared to be secondary to a hypothalamic abnormality since on two occasions the patient had a marked plasma ACTH response to vasopressin but not to insulin induced hypoglycaemia. It is postulated that the deficits of these three adenohypophysial hormones were instrumental in causing a severely impaired aldosterone secretory capacity in response to sodium restriction and an angiotensin infusion. In addition, the patient had an unusual form of thyroid dysfunction that was in part reversed with hydrocortisone replacement. The patient's unfortunate death during a hypoglycaemic crisis allowed correlation between her extensive antemortum endocrine testing and her pathologic anatomy.