Objectives: The aim of this study is to assess the subjective and objective short-term results and safety of transnasal balloon dilatation of the Eustachian tube (BET) in adult patients with chronic dilatory Eustachian tube dysfunction (ETD). Design: Retrospective cohort study. Data collection was performed preoperatively, 1 and 3 months after BET. Setting: Tertiary referral hospital. Participants: A cohort of 42 consecutive patients (66 ears). Main outcome measures: ETDQ-7 score, bone conduction threshold, air-bone gap, the ability to perform Valsalva’s and/or Toynbee’s manoeuvre, tympanic membrane and middle ear conditions were collected pre- and postoperatively. Subjective satisfaction and complications were collected postoperatively. Results: The ETDQ-7 score improved significantly from 4.28 to 3.09 1 month postoperatively and from 4.10 to 2.96 3 months postoperatively. Bone conduction thresholds did not differ significantly postoperatively. A significant improvement of air-bone gap was found postoperatively. The tympanic membrane and middle ear condition showed improvement in 62%. Subjective satisfaction 1 and 3 months postoperatively was around 43 and 48%. A small number of minor (self-limiting) complications did occur. Conclusions: BET has shown to be a safe intervention, which may have a positive effect on objective and subjective indicators for chronic dilatory ETD in adult patients. We observed subjective positive effects in less than half of the patients. For certain indications, there was a measurable positive effect on the findings of the eardrum and ETDQ-7, whereas in other patients it seemed not to have any effect at all. Careful patient selection may improve this success rate. Randomized controlled trials with a prolonged follow-up are required to assess the value of BET in comparison to grommets.