We present two cases of transient central diabetes insipidus in preterm neonates with post-hemorrhagic hydrocephalus. Although the association between intraventricular hemorrhage and diabetes insipidus has been described in preterm infants, the association between diabetes insipidus and hydrocephalus, and the fact that such central diabetes insipidus could be reversible with the reduction of ventricular size, either because of spontaneous resolution or the placement of ventriculo-peritoneal shunt is first described here in neonates.