Lymphocytic hypophysitis is an uncommon but increasingly recognized disorder characterized by chronic inflammation and destruction of the anterior pituitary. Three new cases are presented here with a review of the 27 previously reported cases. The disease affects primarily young women in late pregnancy or in the postpartum period but also has been described in postmenopausal women and in one man. It presents as an expanding intrasellar mass or as partial or panhypopituitarism. The etiology may be autoimmune. The natural history of this entity begins with enlargement of the pituitary secondary to inflammatory infiltration and progresses to atrophy of the gland with destruction of pituitary tissue and replacement with fibrosis. At least 1 patient had documented recovery of pituitary function, and the overall potential incidence of recoverable function is unknown. Our improved understanding of this disease has led us to conclude that surgical intervention is not always necessary.