This prospective, multicentre trial from China looked at the improvement in Eustachian tube function after endoscopic sinus surgery. Seventy patients from three tertiary units were included in the study. They all completed the Eustachian tube dysfunction (ETDQ-7) and SNOT-22 questionnaires and underwent tympanometry, endoscopy and Valsalva pre and postop at eight-to-12 weeks. The ETD group were elected from within the CRS cohort using ETDQ-7 scores and tympanometry along with symptoms. Objective evidence was sought and improvement in function on ETDQ-7 was defined as in improvement in score by 3.5. Data were collected for 254 sinus patients, reduced to 80 with ETD symptoms and then 70 who completed follow-up. The results showed ETDQ-7, the ability of positive Valsalva and tympanogram were significantly improved in most of the CRS patients eight-to-12 weeks after FESS. Improvement of ETDQ-7 score was observed postoperatively at six months in half of the patients. Preoperative allergic rhinitis and high SNOT-22 scores were associated with poorer outcomes in resolution of ETD symptoms.