This chapter discusses nasal polypi, which are simple oedematous hypertrophied mucous membrane covered by columnar ciliated epithelium. Polypus may be classified as simple polypi, fungal polypi and malignant polypi. Ethmoidal polypi are multiple, bilateral, seen in adults and are due to allergy, while antrochoanal polypi are usually single, unilateral, seen in children and are due to sinus infection. Allergy has been thought to be a major factor causing oedema of the mucosa leading to poor ventilation and drainage of secretions. Cough impulse and transillumination test are useful in the diagnosis. On examination anterior rhinoscopy shows smooth, glossy, multiple, mobile, bluish grey masses like a bunch of grapes. Needle aspiration may be helpful to see cerebrospinal fluid. Radiography will show an opaque maxillary antrum on the affected side, while lateral projection will show a polypoidal swelling in nasopharynx with a column of air behind the mass. Antihistaminics are given to control the allergy.