Antrochoanal polyp is a benign lesion originating from the mucous membrane of the maxillary sinus. When it grows and fills the sinus, it extends through the fontanelle into the nasal cavity and further into the choana and/or nasopharynx. It is typically a unilateral, solitary polyp that is more common in males than females, as well as in children and young individuals. The exact pathogenesis of the polyp is unknown. It commonly presents with unilateral nasal obstruction. Diagnosis is made through nasal endoscopy and sinus CT scan, and the definitive diagnosis is established histopathologically. Treatment of antrochoanal polyps is exclusively surgical, and nowadays it is predominantly performed endoscopically (functional endoscopic sinus surgery, FESS), by a surgical technique that removes the polyp without external incisions, scars, or sutures. It is crucial during surgery to completely remove its intramaxillary component, including the affected mucosa, in order to prevent polyp recurrence. Postoperative monitoring should be conducted for at least 2 years.