To evaluate the results of endoscopic sinus surgery (ESS) in children with chronic sinusitis. The long-term outcomes and the relative factors were analyzed retrospectively.A total of 268 children (432 sides), 186 males and 82 females, aged 3 to 17 years (average, 14.3) were included in this study (underwent ESS). The postoperative follow-up time of 188 cases (305 sides, 70.1%) was over one year. The management during follow-up was adopted under nasal endoscope and local anesthesia. The postoperative treatment included cleaning operative cavity, nasal irrigation, antibiotics, steroid, immune regulator, etc.Overall cases included 89 cases (147 sides) of chronic sinusitis, 86 cases (142 sides) of nasal polyps and 13 cases (16 sides) of mucocele respectively. The cure rate was 70.2% (132 cases). 43 cases (22.9%) were improved, while other 13 cases were of no effect. Overall symptoms, 93.1% children with headache were improved, 85.1% children were free of nasal obstruction and 60.1% children gained a relief of purulent discharge. 11 cases had no change and 2 cases were worse compared with before surgery. 34 cases with anosmia were improved or recovered after ESS. The total effective rate of ESS was 93.1%. 8 cases received a revision ESS.ESS in children with chronic sinusitis and polyps has a good long-term outcomes. The reasonable reservation of mucosa during ESS must be emphasized. The quality of follow-up is an important factor affecting the results of ESS. Whether the disciplinary preoperative management was made or not is the hypothesis of ESS indications.