尿崩症（Diabetes insipidus）由于肾脏集尿管(renal collecting ducts)对抗利尿激素(antidiuretic hormone; ADH, 又称为血管加压素(Arginine vasopressin; AVP)没有反应，造成尿液无法进行再浓缩(concentrate)，进而导致此症患者发生多尿(polyuria)及剧渴(polydipsia)等表征。此症依罹病遗传模式的不同，又可分为两型：

Diabetes insipidus (DI) is a condition characterized by excessive thirst and excretion of large amounts of severely dilute urine, with reduction of fluid intake having no effect on the concentration of the urine. There are different types of DI, each with a different set of causes. The most common type in humans is the neurological form, called central DI (CDI), which involves a deficiency of arginine vasopressin (AVP), also known as antidiuretic hormone (ADH). The second common type of DI is nephrogenic diabetes insipidus (NDI), which is due to kidney or nephron dysfunction caused by an insensitivity of the kidneys or nephrons to ADH. DI can also be gestational, or caused by alcohol or some types of drug abuse. DI should not be confused with nocturia.