Background: Chronic rhino-sinusitis and persistent allergic rhinitis is often cited as risk factor for developing adenoid hypertrophy or adenoiditis, but this relationship has not been studied extensively. In this study, we evaluated the mucosal barrier, squamous changes of ciliated epithelium, IgA secretion and BCL-6 expression in adenoids, and adenoid size. Methods: Six children with allergic rhinitis and sinusitis, nine children with only allergic rhinitis, nine children with only sinusitis and six children without any history of allergic rhinitis and sinusitis were enrolled. H-E stain of adenoid for squamous metaplasia, immunohistochemical study of adenoid for IgA and BCL-6, cytokeratin stain for evaluation of mucosal barrier and lateral view X-ray for adenoid size were performed. ANOVA test was used in the analysis and data showing p value of less than 0.05 were considered significant. Results: The number of ciliated cells had tendency to be decreased and squamous metaplasia had tendency to be increased in three experimental groups (p>0.05). Deterioration of mucosal barrier had tendency to be detected in three experimental groups than control group (p>0.05). BCL-6 had tendency to be increased and IgA secretion had tendency to be decreased in three experimental groups (p>0.05). There is no difference in adenoid size between three experimental groups and control group. Conclusion: Despite the expectation that adenoid would be affectecd by allergic rhinitis and rhino-sinusitis, we found no evidence for influence of adenoid immunity.