Objectives/Hypothesis:Immunoglobulin (Ig)E‐mediated hypersensitivity to fungi has been postulated to explain allergic fungal sinusitis (AFS). Not all patients suspected to have AFS demonstrate systemic evidence of allergy. Locally produced IgE might explain those patients with no systemic evidence of allergy but clinical features of AFS. The aim was to determine whether fungal‐specific IgE could be demonstrated in sinus mucin in patients with eosinophilic mucin rhino‐sinusitis.