Sphenoid sinus mucocele comprises only 2% of all paranasal sinus mucoceles which can compress on the optic canal or inferior orbital fissure, and causing loss of vision. One case with sphenoidal sinus mucocele is reported and discussed. A 45 years-old male was complaining of decrease in vision in the right eye and severe headache at the right-sided. Computed tomography showed a right sphenoidal sinus mucocele with right ethmoidal extension and compressing the right inferior orbital fissure and the right optic nerve. The lesion was removed through an endonasale sphenoidotomy. Histological examination confirmed diagnosis. The patient’s follow-up for the last six months was normal with normal vision. The rarity of sphenoidal sinus mucocele made our case interesting to report.