We present six cases of diabetes insipidus (DI) complicating pregnancy. In three cases, DI was manifested during pregnancy and required the administration of desmopressin acetate (1-desamino-8-D-arginine vasopressin, DDAVP). All these cases exhibited abnormal laboratory data such as an elevation of liver enzymes or a decrease in serum antithrombin III. The remaining three cases had suffered from DI before pregnancy which was well controlled on DDAVP. The clinical courses of these pregnancies were all uneventful subsequent to therapy. If DI is first recognized during pregnancy, attention should be paid to the possibility of abnormal liver function and eclampsia.