Ossifying fibroma of the paranasal sinuses and skull base in paediatric patients is difficult to operate and can recur easily after surgery. This study aimed to analyse factors associated with recurrence after transnasal endoscopic resection of ossifying fibroma in paediatric patients.This retrospective observational study included 34 patients under 17 years of age who underwent transnasal endoscopic resection of ossifying fibroma of the paranasal sinuses and skull base from 2005 to 2021 at a single tertiary medical centre. Clinical indicators such as age; surgical history; pathological type; intraoperative bleeding; and orbit, anterior skull base, sphenoid bone, sella turcica, clivus, or frontal sinus involvement were subjected to univariate analysis using the χ2 test, to investigate whether any of these factors affected recurrence.All 34 patients underwent transnasal endoscopic resection. The follow-up period was 6-120 months (mean: 48.0 months). Five patients experienced local recurrence during the follow-up period (14.7%). Results of χ2 tests indicated that a history of previous surgery, the amount of intraoperative bleeding, and sphenoid and/or sella turcica and clivus involvement were significantly associated with recurrence (P < 0.05). Age; pathological stage; and orbit, anterior skull base, and frontal sinus involvement were not associated with recurrence (P > 0.05).The increased risk of recurrence after transnasal endoscopic resection of nasal-skull base ossifying fibroma should be considered during endoscopic surgery in paediatric patients with a history of previous surgery, intraoperative bleeding tendency, and sphenoid and/or sella turcica and clivus involvement. These patients require careful postoperative follow-up.© 2023. The Author(s).