This study is a retrospective analysis of 21 cases of central diabetes insipidus (CDI) at KTU Faculty of Medicine, Farabi Hospital from January 1987 to December 1995. Their ages ranged from one month to 16 years (mean 5.6±4.2 years), 9 were female and 11 male. Nine children had idiopathic CDI, 5 had DIDMOAD syndrome, 3 had Langerhans cell histiocytosis, 2 had cranioppharyngioma 1 had Alstr�m syndrome, and one had posstraumatic DI. High percentages of idiopathic CDI and DIDMOAD syndrome, were found in our series. Our case with Alstr�m syndrome was the first case associated with CDI, in the literature.