The causes of central diabetes insipidus(CDI) are numerous; some primary cases are idiopathic while most secondary cases are surgically induced or the result of tumor. The frequency of metastatic tumor as a cause of DI is 6% to 20% of cases, Variety of malignancies including breast, lung, colon, prostate cancer, and leukemia/lymphoma have been reported to metastasize to the pituitary, although most patients are asymptomatic. Clinical manifestations of pituitary metastases include anterior pituitary failure, visual disturbance, and extraocular muscle weakness. DI is the most common clinical manifestation of hypothalamic-pituitary axis(HPA) metastases. Anatomical basis far this clinical picture is that most metastases occur in the posterior lobe. We report on a 35-year-old male patient with meningeal involvement of malignant lymphoma that was thought to be associated with DI. Confirmation of primary malignancy was made by biopsy at site of cervical lymph node and tonsil, Pituitary involvement was suspected on brain MRI, and satisfactory symptornatic relief was obtained with vasopressin. Because of the progres- sion of underlying lymphorna that has shown no response to combined anticancer chemotherapy, the patient expired on 60th hospital day. (J Korean Soc Endocrinol 12:596-601, 1997)