© 2021 Japanese Society of Otorhinolaryngology-Head and Neck Surgery, IncObjective: To evaluate the hearing and Eustachian tube functions (ETF) of hot air balloon (HAB) pilots, who are exposed to high altitude occupationally. Materials and methods: The study was designed as a cross-sectional controlled study. Thirty HAB pilots and 30 healthy volunteers were included. Pure tone audiometry and speech discrimination scores (SDS) were used to assess the hearing function. Pure tone average (PTA) was calculated using the hearing thresholds (HT) at the frequencies 500, 1000, 2000, and 4000 Hz. Tympanometry and automatic Williams test (ETF1) were conducted to assess the ETF of the participants. Eustachian Tube Dysfunction (ETD) was defined as the change of tympanometric peak pressure (TPP) at rest (P1) less than in 10 decapascals (daPa) with Valsalva (P2) and Toynbee (P3) maneuvers. Eustachian Tube Dysfunction Questionnaire-7 (ETDQ-7) was also administrated. Results: Mean ages of the participants were 32.03±8.12 and 32.33±9.47 years in the HAB and control groups, respectively (p = 0.865). HTs, PTAs, SDSs, P1, P2, P2-P1 and P1-P3 values were similar in the groups (p > 0.05). P3 values in both ears were significantly higher in the HAB group compared to the control group (p = 0.018, p = 0.002). Positive correlations were detected between the duration of the experience of HAB pilots and their HTs at 4 kHz and 8 kHz (p < 0.05) The prevalence of ETD in at least one ear was 83.7% and in both ears was 43.3% in the HAB group, both of which were significantly higher than the control group (p = 0.001, p = 0.049). The ETDQ-7 scores were also higher in the HAB group compared to the control group (p < 0.001). Conclusion: Both the subjective and objective measures of ETF indicate that ETD is common among the HAB pilots. However, the hearing functions of those seem to be unaffected.