To evaluate the effectiveness of endoscopic surgery in the treatment of antrochoanal polyp (ACP) 26 consecutive cases form February, 1991 through Aprill, 1995 in Seoul National University Hospital were reviewed. Ten cases were treated by osteoplastic Caldwell-Luc antrostomy, 15 cases by endoscopic surgery alone, and 1 case by both of the procedures. In all cases, the polyps were removed completely, and no recurrence was found except the case treated by both of the procedures. The endoscopic removal of the antrochoanal polyp can be an appropriate choice of surgical treatment with low rate of recurrence and complication especially in children.