Endoscopic sinus surgery is utilized as a means of treating medically refractory chronic rhinosinusitis and complicated acute rhinosinusitis for over 30 years. In an effort to improve patient outcomes by technique refinement, improved instrumentation, and an in-depth understanding of endoscopic anatomy, surgeons were able to expand minimally invasive endoscopic surgery to include the treatment of sinonasal tumors, skull base defects, and orbital pathology [1, 14]. Patients are the beneficiaries of less invasive surgery, avoiding facial scars and experiencing less morbidity. Importantly, this is accomplished without compromising long-term success in patients with benign neoplasms of the paranasal sinuses [7, 9, 15, 16]. Early concerns that tumors would be removed piecemeal rather than en bloc and would lead to unacceptable recurrence rates have not been seen. With appropriate endoscopic skills and instrumentation and routine endoscopic surveillance, patients with benign sinonasal neoplasms can be treated safely and effectively. For many surgeons, an endoscopic approach has become the default choice. The purposes of this chapter are to outline the most commonly encountered benign neoplasms, identify unique properties of individual tumors regarding size and location, and discuss specific surgical principles for specific clinical situations.