This study assessed the characteristics of patients with CRS, with or without nasal polyps, who underwent ESS as part of their treatment for sinonasal disease at the Department of ORL HNS, Sisters of Charity University Hospital in Zagreb and compared the results to other studies done on CRS patients. Patients who were operated during a year period of 2016 were audited. The data collected included demographic features of patients, risk factors exposure, diagnosis, and type of endoscopic surgical procedures which were performed to treat the sinonasal disease. The purpose of the study was to understand the characteristics of patients who need ESS as part of their treatment course. In total, 189 patients were included in the study. Of which, 67% of the participants (85 males and 46 females) are diagnosed with CRSwNP and 31% (30 males and 28 females) are diagnosed with CRSsNP, 2% are diagnosed with CRS with tumor. In this study 13 patients were in the age group of <18 years (6.8%), followed by 28 in the age group of 19-30 (14.8%), 54 patients were in the age group of 31-45 (28.5%), 57 patients were in the age group of 46-60 (30%), and 37 patients were above 60 years (19.5%). The mean age for patients with CRSwNP was 49.2 and for the patients with CRSsNP was 38.7. The results showed that male gender was more associated with nasal polyps and that the frequencies of allergy, asthma, and aspirin sensitivity were significantly higher than for patients diagnosed with CRSsNP. Patients with CRSwNP tend to undergo more than one endoscopic procedure compared to patient without polyps. Septal deviation was more prevalent in the CRSsNP group (55%) when compared to CRSwNP (25.2%). The majority of the patients who underwent surgery had multiple sinuses involved (40%). Single-sinus operations were more common among ethmoid (17%) and maxillary (13%) sinuses.