The long term results are reported of transtympanic drains in 391 ears of 258 children affected by serous otitis; 150 ears have been evaluated at the end of a 3-7-year observation period. (1) A high percentage of ears with major anatomical lesions was found (46.6%), especially in the higher age group (greater than 7 years). (2) Functional hearing results are better than anatomical results; 84.6% of the subjects had a hearing level better than 20 dB (0-10 dB: 53.3%; 11-20 dB: 31.3%). (3) Anatomical and functional results are worse in case of recurrence (2 or more drains). (4) It is imperative to control periodically those children with major tympanic lesions and present good hearing.