Little is known about the bacteriology of the middle meatus in children. Therefore, middle meatal samples were obtained from 50 children who underwent adenoidectomy or adenotonsillectomy, while a group of 50 children submitted to minor non-ENT surgical procedures, were used as a control group. Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae were the most frequent cultured organisms, not only in the ENT group (in 68, 50 and 60% of the children respectively) but also in the control group (40, 34 and 50%). These three potential pathogens were more frequently seen among the children of the ENT group but only for H. influenzae was the observed difference statistically significant (P = 0.009). On semiquantitative analysis, there seemed to be more negative cultures or cultures with only a few colonies in the control group, while the richer cultures were obtained from the ENT group. Again, only for H. influenzae, these differences reached a statistical significance (P = 0.003). Streptococcus viridans and Neisseria species, both organisms that might be able to inhibit colonisation by some of the pathogens, were more frequently cultured in the control than in the ENT group: Strep. viridans 30 vs. 10% (P = 0.025) and Neisseria species 14 vs. 2% (P = 0.069).