OBJECTIVE: Determining the clinical predictors of long-term success after endoscopic sinus surgery (ESS) would better guide the management of patients. METHODS One hundred-thirty chronic rhinosinusitis (CRS) patients were evaluated retrospectively. Overall subjective improvement was 83% with a mean follow-up of 60 months. Eighty percent had anatomic variations; 36.2%, allergy; 55.4%, nasal polyps; and 26.9%, history of previous operation. The improvement was 100%, 94%, 79.5%, and 69.7% in stages 0, I, II, and III, respectively. With other parameters, the success rates were 68.1% and 91.6% with and without allergy, 73.6% and 94.8% with and without polyps, 54.3% and 93.7% with and without previous history of surgery, 84.4% and 82.7% with and without anatomic variations, and 23.8% and 94.4% with and without recurrent polyps. CONCLUSION: In multivariate Cox regression analysis, allergy (P < 0.05; relative risk, 4.6) and previous polypectomy (P < 0.05; relative risk, 9.9) were found to be predictors of poor prognosis in the long-term follow-up.