Mucocele of the paranasal sinuses is a rare disease with slow evolution. It is a benign, encapsulated and destructive formation fi lled with mucous fl uid and tapistrated with respiratory epithelium. Of all the paranasal sinuses, the sphenoid sinus is aff ected in only 1-7% of the cases. We present two cases of mucocele of the sphenoid sinus involving the posterior ethmoidal cells. We consider here their clinical presentation, use of neuroimaging in the diagnosis, surgical care and postoperative results. Both patients presented with a history of persistent headache and in addition, one of them had a paresis of the right oculomotor and abducens nerves. A transnasal endoscopic sphenoidectomy was performed in both patients, in one -with an evacuation of the mucocele and marsupialization, and in the other -with a balloon dilatation of the natural foramen of the sinus. Postoperatively, a complete reversal of the symptoms was observed in both patients. Mucocele of the paranasal sinuses should be considered as a diagnosis in cases of persistent headache with a primarily retrobulbar location and eye symptoms. Computed tomography and magnetic resonance imaging can be used to successfully diagnose the disease. The transnasal endoscopic sphenoidectomy is the therapeutic method of choice which allows evacuation of the mucocele, while the marsupialization allows good drainage and prevents recurrence.