Epithelial changes in nasopharyngeal orifice of eustachian tube in 15 patients with otitis media with effusion (OME) were studied. Ultrastructural examination of the epithelium revealed distinct alterations in the ciliated cells, intermediate cells and in the columnar cells with microvilli. The ciliated cells were the predominant cell type in the epithelium and were characterized by compound cilia and apical cytoplasmic bulgings with fine granular content. The intermediate cells showed more prominent lateral cytoplasmic bulgings. Cytoplasmic bulgings of both cell types eventually pinched off and set free as cytoplasmic bodies, similar to the cytoplasmic bodies derived from lymphocytes. As a result of epithelial destruction, the lumen of nasopharyngeal orifice was occupied by epithelial cellular debris among which leucocytic cells and cytoplasmic bodies with fine granular content. This accumulation in the lumen probably developed as a result of defective mucociliary activity which is due to compound cilia formation in the ciliated cells. Moreover, ultrastructural resemblance of cytoplasmic bodies derived from ciliated cells, intermediate cells and leucocytic cells indicates the possible role of these cells in common immune defence mechanisms in chronic otitis media with effusion.