Bardet-Biedl syndrome is a rare disease involving rode cone dystrophy, polydactyly, obesity, learning disabilities, hypogonadism and renal anomalies, symptoms caused by immotile cilia dysfunction. We report the first case of this syndrome in a teenager with an endonasal mass secondary to pyocele of a concha bullosa. The patient was treated successfully with endoscopic sinus surgery. Nasal obstruction secondary to a middle turbinate pyocele in Bardet-Biedl syndrome has not been described before. The pediatrician and the rhinologist should take this entity into consideration when investigating patients with Bardet-Biedl syndrome and sinonasal symptoms.