We reported 4 cases of lymphocytic infundibuloneurohypophysitis. All four patients had diabetes insipidus as initial symptoms without anterior pituitary dysfunction. All patients showed pituitary stalk swelling and two patients showed enlargement of the pituitary gland. No patients were operated on for a histological diagnosis. No patients received corticosteroid treatment for this pathology. The mean follow-up period was 36 months. The diabetes insipidus continued in all cases, but radiological findings showed improvement in all cases. In one case, adrenal insufficiency occurred after 10 months, but had disappeared 6 months later. We think lymphocytic infundibuloneurohypophysitis can be diagnosed without histological examinations and can be treated conservatively without corticosteroid treatment. It seems to be a self-limiting disease. This disease can be distinguished from lymphocytic adenohypophysitis, but in some cases, both the anterior and posterior pituitary glands are invaded, and in this situation lymphocytic hypophysitis may be an appropriate name. Even if the initial symptom is diabetes insipidus, careful follow-up is needed for the duration of the disease.