The aim of this study was to verify the frequency of atypical bacterial infections in children undergoing tonsillectomy because of severely recurrent acute tonsillopharyngitis (AT) and the possible benefit of surgery in cases in which Mycoplasma pneumoniae and Chlamydophila pneumoniae seem to play a role in causing the recurrences. A total of 118 patients (76 males; mean age +/- standard deviation, 6.67 +/- 3.31 years) were enrolled: 59 underwent tonsillectomy because of severely recurrent AT and 59 underwent adenotonsillectomy because of obstructive sleep apnea syndrome (OSAS). The results show, for the first time, that the great majority of children with a history of severely recurrent AT (and, therefore, considered to be eligible for elective tonsillectomy) are infected by atypical bacteria, mainly M. pneumoniae, and that tonsillectomy seems to be effective in reducing the recurrence of both AT and acute respiratory disease during 12 months follow-up postsurgery.