We describe the autopsy findings in a 24-year-old woman with a clinical picture of pituitary and adrenal insufficiency which had its onset shortly after a normal pregnancy and delivery of a normal infant, two years before the mother's death. There were heavy lymphocytic infiltrations of the adenohypophysis, thyroid, and adrenals as well as diffuse retroperitoneal fibrosis with numerous perivascular lymphocytic infiltrates. It is concluded that lymphoid hypophysitis probably represents the hypophyseal counterpart of other endocrine autoimmune disorders and that immune mechanisms may also play a role in the pathogenesis of the so-called idiopathic retroperitoneal fibrosis.