PURPOSE: Gestational diabetes insipidus (GDI) is a rare endocrinopathy complicating about 4:100,000 deliveries. We present the case of a preterm parturient with GDI and severe hypernatremia (serum sodium concentration = 174 mmol.L(-1)) presenting for an urgent Cesarean section. CLINICAL FEATURES: Fluid resuscitation and desmopressin supplementation partially corrected the patient's homeostasis, allowing us to carefully titrate epidural anesthesia for an urgent Cesarean section. After delivery, the patient was transferred to the intensive care unit. The serum sodium concentration of the mother and the neonate was normalized over 48 hr and three days respectively. CONCLUSION: The careful perioperative management of GDI led to a favourable outcome of the mother and fetus.