Under physiological conditions, fluid and electrolyte homoeostasis is maintained by the kidney adjusting urine volume and composition according to body needs. Diabetes Insipidus is a complex and heterogeneous clinical syndrome affecting water balance and characterized by constant diuresis, resulting in large volumes of dilute urine. With respect to the similarly named Diabetes Mellitus, a disease already known in ancient Egypt, Greece and Asia, Diabetes Insipidus has been described several thousand years later. In 1670s Thomas Willis, noted the difference in taste of urine from polyuric subjects compared with healthy individuals and started the differentiation of Diabetes Mellitus from the more rare entity of Diabetes Insipidus. In 1794, Johann Peter Frank described polyuric patients excreting nonsaccharine urine and introduced the term of Diabetes Insipidus. An hystorical milestone was the in 1913, when Farini successfully used posterior pituitary extracts to treat Diabetes Insipidus. Until 1920s the available evidence indicated Diabetes Insipidus as a disorder of the pituitary gland. In the early 1928, De Lange first observed that some patients with Diabetes Insipidus did not respond to posterior pituitary extracts and subsequently Forssman and Waring in 1945 established that the kidney had a critical role for these forms of Diabetes Insipidus resistant to this treatment. In 1947 Williams and Henry introduced the term Nephrogenic Diabetes Insipidus for the congenital syndrome characterized by polyuria and renal concentrating defect resistant to vasopressin. In 1955, du Vigneaud received the 1955 Nobel Prize in chemistry for the first synthesis of the hormone vasopressin representing a milestone for the treatment of Central Diabetes Insipidus.