A 27-year-old man was admitted to our hospital with facial erythema and general malaise. He had previously suffered from orbital myositis, central diabetes insipidus (DI), peripheral neuritis, and hypogonadotropic hypogonadism. Physical and immunological examinations revealed that he was suffering from systemic lupus erythematosus (SLE). Magnetic resonance imaging of the hypothalamic-pituitary region demonstrated a significant enlargement of the pituitary stalk and posterior pituitary. Endocrinological examinations showed that he had not only DI and hypogonadotropic hypogonadism but also hypoadrenalism and hypothyroidism, which were ascribed to the pituitary stalk lesion. Lymphocytic infundibuloneurohypophysitis associated with SLE was diagnosed. Administration of 30 mg/day of prednisolone for one month resulted in a marked reduction of the pituitary stalk thickening and posterior pituitary. It is recommended that a pharmacological dose of glucocorticoid be used in the treatment of lymphocytic hypophysitis patients who show significant thickening of the pituitary stalk and/or a large pituitary mass.