The antrochoanal polyp (Killian polyp) is an infrequent, benign neoplasm, which arises from the maxillary sinus to reach the ipsilateral choana. The treatment of this disease is essentially surgical, by means of a wide antrostomy. The aim of the study was to compare the results obtained on 23 consecutive cases of antrochoanal polyps endoscopically treated between February 1997 and January 2000 with those reported in the literature, with particular regard to the surgical technique adopted, the histological features, the patterns of its development and the clinical outcomes. The histology revealed in most of the cases a cystic aspect surrounded by edematous stroma. In all cases the polyp emerged from the middle meatus, mostly starting from the upper-lateral (zygomatic) wall of the antrum. All patients were endoscopically followed-up for an average period of 39 months (17-61). We observed two recurrences, both in pediatric cases who evidently underwent an incomplete surgical removal of antral mucosa at its inferior aspect, probably due to the fear of damaging the teeth buds. We did not observe any postsurgical complication. Our data indicate the endoscopic middle meatal antrostomy as the optimal approach, also for the revision cases and in children.