Revision endoscopic sinus surgery is performed when symptoms associated with sinusitis persist after sinus surgery and despite continued medical therapy. The causes of treatment failure are varied and may include systemic, mucosal, and anatomic factors associated with persistent inflammatory disease. The purpose of this retrospective review was to define the sites of recurrent or persistent sinonasal disease in patients undergoing revision endoscopic sinus surgery. This data was based on our preoperative CT scan and nasal endoscopy, as well as intraoperative findings. This study includes an evaluation of the most recent sinus surgery in a group of 153 patients and 265 operated sides. The frequency and distribution of regional anatomic sites of disease is presented and discussed.