Paranasal sinus mucoceles are benign, space-occupying, cystic lesions that require a surgical treatment. An endoscopic endonasal marsupialisation is nowadays the surgical approach of choice in most of the cases. The aim of the present study is to validate this option and to determine the clinical characteristics of paranasal sinus mucoceles. A retrospective study based on the clinical experience of several ENT surgeons was performed using a standardised questionnaire. The respondents participate to a report on endoscopic endonasal surgery for non-inflammatory disease in Belgium. One hundred and fourty patients presenting 178 mucoceles were included in this study. Primitive mucoceles were reported in 35% of the patients, posttraumatic mucoceles in 2.1% and postoperative mucoceles in 62.9%. The time interval between first rhinologic procedure and the mucocele diagnosis was respectively 24.4 months after FESS and 108.3 months after an external procedure. Paranasal sinus mucoceles predominantly occur in the fronto-ethmoidal region (64%), followed by the maxillary sinus (18.6%), the sphenoid sinus (8.4%) and the posterior ethmoid sinus (6.7%). Uncommon locations were also reported in 2.3% (Inferior turbinate, middle turbinate, pterygomaxillary space). Endoscopic endonasal marsupialisation (combined with an external procedure for 8 patients) was successful in 97.9% of the patients. Only 3 patients showed recurrence. Endoscopic endonasal marsupialisation of paranasal sinus mucoceles is a reliable therapeutic option with favorable results and is supported by the questioned ENT surgeons in Belgium.