Sphenoid sinus mucoceles represent only 1-2 per cent of all paranasal sinus mucoceles. Patients may present with a myriad of symptoms. Pre-operative investigations include nasoendoscopy, computed tomography and/or magnetic resonance imaging. Treatment is by endoscopic sinus surgery. A retrospective review of the archives of the Singapore General Hospital otolaryngology department (1999-2006) identified 10 cases of sphenoid sinus mucocele. Patient demographics, presenting symptoms, investigations and treatment were evaluated. The 10 patients identified (three women and seven men) had a mean age of 54.5 years (range 24-70 years). Thirty per cent of patients had a history of nasopharyngeal carcinoma treated with radiotherapy. Presenting symptoms, in order of decreasing frequency, were: ocular symptoms (50 per cent), headaches (30 per cent), nasal discharge (30 per cent) and facial pain (10 per cent). All patients underwent pre-operative computed tomography or magnetic resonance imaging. Twenty per cent of patients had evidence of intracranial involvement on imaging. All patients underwent uncomplicated transnasal sphenoidotomy and drainage of the mucocele. There was no clinical or radiological evidence of recurrence at a mean follow up of 29 months (range 4-90 months). Sphenoid sinus mucocele is a rare condition. In this study, radiation to the head and neck appeared to be a predisposing factor, and eye symptoms were the commonest presentation. Endoscopic sinus surgery is a safe and effective treatment modality.