Although mucocele is a benign lesion, its unavoidable expansions may result in irreversible damages in adjacent organs. In spheno-ethmoid mucoceles which are extremely rare, this condition may cause more severe problems. Central diabetes insipidus, developed secondary to sphenoid sinus mucocele, was detected in a 54-year-old male patient, who underwent endoscopic sinus surgery 2 times due to nasal polyposis. Endoscopic sphenoid mucocele marsupialization was performed to the patient, but despite partial regression in the 1-year follow up, complete recovery was not observed. (C) 2014 Elsevier Inc. All rights reserved.