We report a case of AML with diabetes insipidus (DI). A 68-year-old female was admitted to our hospital because of fever and leukocytosis. The WBC was 197,000/microliter with 98% blasts positive for myeloperoxidase, CD33, CD34 and HLA-DR. While, on admission, urine volume was more than 6 liters daily. Blood vasopressin level was 0.3 microgram/ml. The patient was diagnosed as having AML with DI. By chemotherapy consisting of BHAC, DNR, 6-MP and PSL and intrathecal administration of AraC, MTX and PSL, and nasal drip of DDAVP, complete remission was attained and the urine volume was reduced to normal. Finally DDAVP became unnecessary. Although the exact cause of DI cannot be ascertained, rapid increase of leukemic blasts and leukostasis in small vessels might be associated with hypothalamus-pituitary system damage. Reportedly, DI is a rare complication of leukemia and administration of DDAVP could be halted in only two patients with leukemia and DI.