Sinonasal inverted papilloma has a high tendency for recurrence, local bone destruction and risk of malignant transformation. Therefore, complete resection of the tumour is required, and close follow up is essential. This article describes the clinical outcomes, recurrence rate and malignant transformation rate of sinonasal inverted papilloma. In this study, 139 patients diagnosed with sinonasal inverted papilloma in our hospital from December 2010 to May 2022 were retrospectively analysed. All patients underwent endoscopic surgery. Sinonasal inverted papilloma occurred more often in males than in females. The mean age of patients with sinonasal inverted papilloma was 67.3 ± 5.7 years at diagnosis. The most prevalent site of origin was the maxillary sinus (50.4 per cent). The recurrence rate was 5.75 per cent, and the malignant transformation rate was 6.5 per cent. All patients in this study underwent endoscopic surgery. Meticulous resection and regular long-term follow ups are crucial to reducing sinonasal inverted papilloma recurrence after surgery.