Recurrent or chronic adenotonsillar infections mainly affect children and frequently involve otherwise healthy subjects. Therefore, having excluded systemic immunological deficiencies, this disease may be due to a local dysfunction of the epithelial structures at either the rhino or oropharyngeal level. The aim of the present investigation was to analyze structural and immunological aspects of tonsils and adenoids in subjects who underwent adenotonsillectomy because of recurrent inflammatory episodes with fever. Histological studies and analyses of the cytokine patterns were carried out in palatine tonsils and adenoid samples from 105 patients who underwent adenoidectomy and bilateral extracapsular tonsillectomy for chronic inflammatory hypertrophy of these organs; 46 of the 105 cases examined presented hyperkeratosis of the crypt epithelium; in the remaining 59, the epithelium was hyperplastic with no signs of keratosis. Scanning electron microscopy revealed a continuous epithelial surface of polygon-shaped flattened cells with fissures towards the cryptic depressions. Titration of interleukin-1beta and tumor necrosis factor alpha in serum and tissues demonstrated higher concentrations in the adenotonsillar specimens, whereas the rise in interleukin-6 was more modest.