Objective:To enhance the awareness of masked central diabetes insipidus by introducing three cases and reviewing literature. Methods:The common characteristics of these cases were analyzed

and literature from CNKI

VIP as well as Pub Med database was searched and 9 relative case reports were found out. Results:Our cases all presented with classic hypopituitarism symptoms and increased urine volume

serum sodium

serum chloride as well as serum osmotic pressure after cortisol replacement. They also presented with decreased urine gravity. Two of them finished water deprivation and AVP injection test with a over 9 % increase in urine osmotic pressure as a result. The other started on desmopressin and presented with significant urine volume reduction. Conclusion:Masked central diabetes insipidus is not frequent. However

when hypopituitarism patients encountered polyuria with decreased urine osmotic pressure after cortisol replacement

it should be considered the possibility of coexisting diabetes insipidus.