AbstractMiddle meatus samples were cultured in 120 children undergoing adenotonsillectomy with, or without, insertion of ventilation tubes. Every child (except one) had positive cultures. Haemophilus influenzae (62 per cent of the children), Moraxella catarrhalis (53 per cent) and Streptococcus pneumoniae (48 per cent) were the most commonly isolated bacteria. The presence of Moraxella catarrhalis and (to a lesser extent) Streptococcus pneumoniae was higher in younger children, while Haemophilus influenzae was cultured independently of age.Culture results of these middle meatal samples, carefully taken in order to avoid any contamination, probably reflect some ongoing sinus infection in these children requiring adenotonsillectomy. The problems inherent in the interpretation of surface cultures are addressed.