The endoscopic intranasal appearance of 211 adult patients with cystic fibrosis was studied. The prevalence of nasal polyps in this study was 37%. The commonest nasal symptoms were discharge, headache and obstruction. Intranasal endoscopy usually demonstrated mucosal oedema and thin, clear discharge. The prevalence of allergy, as diagnosed by skin prick testing, was almost twice that of the general population. Tympanometry showed that middle ear effusion was uncommon in these patients.