Although the literature is replete with papers discussing the results of surgery for chronic inflammatory sinus disease, critical comparison of results is difficult due to limited knowledge of the prognostic factors and the variable criteria reported for success. Detailed prospective and retrospective data collection was therefore undertaken to evaluate the results of surgical intervention in 120 patients who underwent endoscopic sinus surgery. Results were evaluated both by symptom questionnaire and by endoscopic follow-up examination. Over 240 data fields were collected on each patient, including information regarding presenting symptoms, endoscopic and computed tomography (CT) findings and surgical procedures performed. In order to reduce potential bias, the results of the follow-up questionnaires were compared to questionnaires from other patients unable to return for follow-up endoscopy. Mean follow-up time was 18 months. Potential prognostic variables were evaluated statistically. A strong correlation was identified between the extent of disease and the surgical outcome. Other identified potential factors appeared to have little or no significance. Therefore, a staging system for inflammatory sinus disease based on the extent of disease is suggested.