The authors report two cases of lymphocytic hypophsitis: a 38-year-old male patient with headache and diabetes insipidus and in a 64-year-old female patient with headache. Magnetic resonance(MR) image of the patients showed mass-like lesions in the hypophysis as well as loss of high signal on T1-weighted MR images. There was evidence of hypopituitarism. Both patients underwent transsphenoidal approaches for histological diagnosis, which was compatable with lymphocytic hypophysitis. When MR image reveals a characteristic pituitary in the hypophysis lesion with relevant clinical symptoms in a patient, one should include "lymphocytic hypophysitis" as one of the diagnostic possibilities, since the therapeutic options are different from those of pituitary tumors.