This study compared nasopharyngeal sepsis with under-aeration ear disease. Nasopharyngeal sepsis was assessed by culture taken directly from the surface of removed adenoid tissue. 156 cases were studied; 100 showed varying degrees of middle-ear under-aeration and 56 had no active ear disease or history of it. In addition, an assessment of post-nasal obstruction was made and this too was compared with middle-ear status. The conclusions suggested that, whilst normal ears can exist in the presence of accepted nasal pathogens, diseased ears are rarely seen in the absence of nasal sepsis. The degree of post-nasal obstruction seemed irrelevant. The commonest nasopharyngeal pathogen was Haemophilus influenzae and when found alone this had a particularly detrimental affect on middle-ear aeration, causing a significant incidence of mucoid middle-ear effusion in this group.