Mucosal specimens of the middle ear from patients who had chronic otitis media were studied and compared with normal middle ear specimens using a scanning electron microscope. The epithelia in chronic otitis media were usually thick and those surface structures varied depending on the area in which the biopsy was taken. Moreover, the structure was not uniform even in the same specimen. Some areas showed a great number of secretory cells, while others demonstrated high population of ciliated cells. Areas with loss of the superficial layer were also observed in a few cases. There were less ciliated cells than we expected. They were not evenly distributed, except for the eustachian tube region. Morphologically, most of these ciliated cells seemed to be normal, and a few isolated atrophic ones were also observed. In cholesteatoma cases, squamous epithelia with desquamating, flat and keratinized cells were observed.