Nasal polyposis is a common problem in otolaryngology. The cause remains unclear, and treatment with medication and surgery is often unsatisfactory. We present our controlled study, which suggests a strong association between food allergy and nasal polyposis. The study was conducted in 2 parts. A postal survey of 900 patients with nasal polyps showed 53 respondents (5.9%) had a known food allergy. In the prospective study, 80 nasal polyp patients and 36 control subjects completed intradermal tests for food allergy. Sixty-five nasal polyp patients (81%) and 4 control subjects (11%) had positive intradermal food test results. This is highly significant. We believe that food allergy may play a significant role in the pathogenesis of nasal polyposis and should be further studied.