Objectives: To introduce a new surgical technique for endoscopic removal of the antral portion of antrochoanal polyp (ACP) by powered instrumentation and to determine its efficacy by measures of relevant patient outcome. Study Design: Prospective study in 28 patients undergoing endoscopic sinus surgery for ACP by our surgical technique. Methods: Improvements of clinical symptoms and endoscopic and computed tomographic findings were evaluated post-operatively with a follow-up period ranging from 12 to 52 months. All symptom scores on a 100-mm visual analogue scale before operation were compared with those at the last visit after operation. Postoperative endoscopic and computed tomographic findings were graded using a three-point scale ranging from 0 to 2. In surgical technique, the antral portion of ACP was identified through the enlarged ostium under intranasal endoscopy and removed by a blade of powered instrumentation that was inserted through the canine fossa. Results: Symptom scores were all significantly reduced postoperatively. All but one patient showed improvement in clinical symptoms and endoscopic and computed tomographic findings during the follow-up period. There were no major complications specific to this technique. Conclusion: Our technique provides an attractive alternative to other methods for removing the antral portion of an ACP and is associated with excellent outcomes and minimal morbidities.