OBJECTIVE: Generation of pilot data for planning of prospective BET-studies for treatment of dilatory Eustachian tube (ET) dysfunction in children. STUDY DESIGN: Retrospective multicenter analysis. SETTING: Nine ENT departments at tertiary care teaching hospitals. PATIENTS: 4-12-year-old children with chronic otitis media with effusion (COME) for more than 3 months or more than 3 episodes of acute otitis media during the last year, having failed standard surgical therapy at least once. INTERVENTION: BET with or without paracentesis, ventilation tube insertion, or tympanoplasty. MAIN OUTCOME MEASURES: Tympanic membrane appearance, tympanometry, and hearing threshold. RESULTS: Two hundred ninety-nine ETs of 167 children were treated. Mean age was 9.1 years (95% confidence interval [95% CI]: 8.7-9.4 yr). In 249 ears (83.3%), COME and/or retraction of the tympanic membrane were the indication for BET. Median hearing threshold was 20 dB HL (95% CI: 0-46 dB). One hundred fifty-five ears (51.8%, 95% CI: 46.1-57.4%) showed a tympanogram type B. Treatment consisted of BET without other interventions ("BET-only") in 70 children, 128 ears. Median length of follow-up for 158 (94.6%) children was 2.6 months (95% CI: 0.3-16.1 mo). After treatment, the tympanic membrane appeared normal in 196 ears (65.6%, 95% CI: 60.0-70.8%, p < 0.001). Median hearing threshold improved to 10 dB HL (95% CI: 0-45 dB, p < 0.001). Tympanograms shifted toward type A and C (type A: 39.1%, 95% CI: 33.7-44.7, p < 0.001). These improvements were also observed in subgroup analyses of "BET-only" treatment and the indication of "COME" respectively. CONCLUSION: BET is improving a variety of dilatory ET dysfunction-related ear diseases in children. This study provides detailed data for design and planning of prospective studies on BET in children.