Maintenance of serum sodium and water balance is a key feature of normal physiology; mediated through the regulation of water intake and renal water loss. Adipsic and hypodipsic disorders are characterized by inadequate spontaneous fluid intake due to defects in osmo-regulated thirst. Patients deny thirst and do not drink, despite dehydration and hypovolaemia. The hypothalamic osmoregulation of thirst and Vasopressin (AVP) production are functionally linked, though anatomically discrete and separate. However, because of the close anatomical relationship of the osmo-sensing mechanisms, adipsic syndromes are often associated with defects in osmo-regulated AVP release: Adipsic Diabetes Insipidus (ADI). A number of different forms of ADI have been described. This presentation will cover the pathophysiology and management of ADI, focusing on practical and pragmatic approaches to sustainable care.