We report the clinical outcomes for 28 subjects treated for inverted maxillary sinus papilloma between 2003 and 2007 involving preoperative imaging determination of tumor origin. Tumor origin often determines whether endoscopic endonasal or transmaxillary surgery is to be done. Endoscopic endonasal surgery was conducted for tumors originating in the posterior maxillary sinus in 17 patients and endoscopic transmaxillary surgery for tumors originating in the anterior maxillary sinus in 11 patients. Recurrence was seen in only 1 whose tumor originated in the superior sinus wall and had spread wide by to the lateral and posterior walls. Endoscopic endonasal resection was initially conducted and the recurrent tumor extracted by endoscopic transmaxillary surgery. The tool essential for successful tumor removal is complete surgical resection so as our study demonstrates, the preoperative determination of tumor origin is important in selecting of the most appropriate surgical procedure.