Functional endoscopic surgery affords the potential for dramatically reducing operative morbidity of surgery for paranasal sinus mucoceles by offering a minimally invasive approach under local anesthesia. Following surgery, direct endoscopic visualization of the area enables accurate follow-up. Unlike sinus obliteration, the ability to accurately image the sinus by CT is also preserved. This paper presents our preliminary experience with 18 mucoceles in which endoscopic sinus surgery was attempted. Five patients had preoperative proptosis and diplopia, three had Pott's puffy tumor and five had erosion of the posterior table of the frontal sinus. Fifteen patients were satisfactorily treated endoscopically, two lesions could not be satisfactorily approached and required external surgery, and one patient had persistent disease. No disease recurrence has been noted to date with endoscopic follow-up of up to 42 months.