Interest in the surgical treatment of chronic rhinosinusitis has increased, primarily because rigid endoscopy and, more particularly, computed tomographic scanning have facilitated the visualization of disease. At the same time it has become both scientifically and financially imperative to audit therapeutic outcome. Consequently, a staging system for nonneoplastic sinus disease is needed. It is clear that any assessment of medical or surgical therapeutic response requires a method of quantifying disease severity that will be widely accepted by practitioners in the field. This acceptance will largely depend on how easy the method is to apply. With computed tomographic scanning it is possible to more accurately determine the extent of the pathologic condition in rhinosinusitis, a disease in which the severity of symptoms and the appearances on nasal endoscopy have a significantly more unpredictable correlation with the extent of disease. One goal of the Task Force on Rhinosinusitis of the American Academy of Otolaryngology-Head and Neck Surgery was to recommend a system for outcomes research that combines quantification with ease of application.