Temporal bones (1,383) from 713 patients were studied systematically for multiple pathologic lesions. Eleven percent (152 temporal bones) were found to have more than one pathologic finding. Males (60.5%) had multiple diseases more commonly than did females (37.7%). The most frequently occurring findings were otitis media (71.1%), otosclerosis (43.4%), endolymphatic hydrops (38.8%), labyrinthitis (25.0%), and cancer (24.3%). We conclude that multiple coexisting pathologic conditions can have coincidental or causative relationships. The otolaryngologist should consider multiple pathologic conditions when diagnosing and treating diseases of the ear.