Choanal stenosis is usually a congenital anomaly in children. Acquired choanal stenosis after radiotherapy for nasopharyngeal carcinoma is a very rare pathology; only two publications report seven cases in the literature. We describe the clinical history, preoperative evaluation, surgical treatment and outcome of a case of acquired choanal stenosis after radiotherapy. The patient, a 56-year-old woman, presented with a history of nasopharyngeal carcinoma (T2- NO-MO) one year before that had been successful treated with radiotherapy (68 Gy). At the end of radiotherapy, she complained of complete nasal obstruction, anosmia and hearing loss due to a bilateral serous otitis media. Bilateral complete choanal stenosis was confirmed by endoscopy and CT scan. Functional endoscopic surgery was performed, and nasal stents were left in place for 3 weeks. One year after, the patient have good airflow, and a patent nasopharynx without choanal stenosis. In conclusion, choanal stenosis is an unusual complication of radiotherapy that can be successfully treated with transnasal endoscopic resection.