Diabetes insipidus in pregnancy has different causes. The association of diabetes insipidus with disturbances of liver function has been reported, however, diabetes insipidus has rarely been reported in HELLP syndrome. We present a 23‐year‐old primigravida with a singleton gestation complicated by HELLP syndrome who developed postpartum diabetes insipidus. Labor was induced promptly to terminate pregnancy because of intrauterine fetal death and liver dysfunction. 1‐deamino‐8‐D‐arginine‐vasopressin was administered. Diabetes insipidus and liver dysfunction resolved within 2 weeks. Development of diabetes insipidus may result from increased vasopressinase activity mainly caused by deterioration of liver functions caused by HELLP syndrome. In pregnant women with liver disease as a result of any cause, the development of diabetes insipidus should be assessed with particular attention.