Carcinoembryonic antigen (CEA) has an important role as a tumor marker and also as a cell adhesion molecule. The expression and the role of CEA in chronic inflammation of middle ear mucosa has not been studied previously. Immunohistochemical analysis with monoclonal antibodies against human CEA was performed in order to detect CEA in formalin fixed and paraffin embedded biopsy specimens of middle ear mucosa in chronic otitis media. In this study 118 specimens of middle ear mucosa from different regions of the middle ear cleft were analysed. All specimens were taken during surgery of otitis media with and without cholesteatoma. The results showed that CEA expression was present in mucosal samples in chronic otitis media with cholesteatoma, predominantly in squamous epithelium, as well as in the subepithelial layer and among the connective tissue, especially on collagen fibres of fibroproliferative stroma. CEA was seen on endothelial cells of blood vessels. Occasionally it was present on the surface of columnar epithelium of the middle ear mucosa in chronic otitis media without cholesteatoma. The expression patterns of CEA in chronic inflammation of middle ear mucosa suggest potential functional activities similar to adhesion molecules and signal regulatory proteins which will be the subject of further study.