Clinical observation of patients with fluctuant sensorineural hearing loss following or occurring with chronic otitis media led to the hypothesis that endolymphatic hydrops can result from chronic otitis media. Illustrative case reports are described. This hypothesis resulted in a temporal bone study of 560 cases in which 109 temporal bones demonstrated the presence of hydrops and 194 evidenced otitis media. Seventy-five cases demonstrated both otitis media and hydrops, of which 20 cases were selected for more detailed histo-pathological study. An interesting finding was the presence of apical hydrops in every case of the latter group. Statistical interpretation of this data helped rule out a coincidental or chance occurrence. A discussion of this clinical relationship included the significance of subclinical (silent) otitis media as a possible cause of endolymphatic hydrops.