Lymphocytic adenohypophysitis (LAH) is an uncommon disorder in the spectrum of pituitary disease. Twenty-three cases proven by biopsy or at autopsy have been reported since 1962. We report 2 further cases and review the etiology, immunology and pathology of the disease. The diagnosis should be considered in a female patient who presents during the post-partum period with the clinical picture of a non-functional or prolactin cell pituitary adenoma and evidence of hypopituitarism.