Previous studies have highlighted that baseline Sinonasal Outcome Test 22 (SNOT-22) score affects surgical outcomes in chronic rhinosinusitis (CRS) and suggested that a SNOT-22- based approach might ameliorate patients’ understanding of expectations after treatment. Our study aimed at verifying this hypothesis in an Italian CRS population. In 457 CRS patients treated with endoscopic sinus surgery after failure of maximal medical therapy, the percentage of achieving a minimal clinically important difference (MCID) and the percentage of relative improvement after surgery were calculated. Moreover, the impact of several factors on preoperative and postoperative SNOT-22 score was investigated. Symptom improvement occurred in the majority of patients and was directly proportional to baseline SNOT-22. 79,7% of patients achieved the MCID and the percentage of relative improvement was 50,1%. Psychological and social-functioning implications significantly affected SNOT-22 scores. Multiple regression analysis showed that history of previous surgery, asthma, preoperative endoscopic and SNOT-22 scores predicted the postoperative SNOT-22 score (R2 = 0,298). Submitting CRS patients to SNOT-22 prior to surgical treatments might help to inform about probable outcomes, although it is strongly influenced by individual perception. Further studies are needed to identify an effective set of subjective and objective parameters for evaluation of outcomes.