Multiple-frequency tympanometry (MFT) and conventional 226-Hz tympanometry were performed in 86 ears of children affected by acute otitis media (AOM) after therapy. In a 3-month follow-up period, the recurrence rate of AOM and persistence of middle-ear effusion in these children were evaluated in comparison with the early results of the two methods, as well as the relation of MFT findings to the possibility of development of AOM sequelae. It seems that abnormal resonant frequency values and recordings by MFT right after an episode of AOM indicate persistence of changes in the mass and stiffness balance of the middle ear, not demonstrated by conventional tympanometry, that could be responsible for a higher probability of AOM sequelae.