Introduction: Eustachian tube dysfunction is a common condition in everyday ENT practice. This study was done to find the effectiveness of transnasal endoscopic balloon dilatation of eustachian tube for treatment of chronic eustachian tube dysfunction. Materials and methodology: Forty patients who were diagnosed with ET dysfunction were assigned to the study. A balloon catheter was used to dilate the cartilaginous part of eustachian tube using transnasal endoscopy. Pre operatively all the patients underwent a complete clinical examination of ear , nose and throat , pure tone audiometry ,tympanometry and thin layer CT temporal bone .Endoscopy was done for all the patients to rule out any pathology in the nose and nasopharynx. Post operatively, symptomatic improvement , Valsalva maneuver ,tympanometry of the patients were assessed . Results: Eustachian tube was dilated with balloon catheter under endoscopic vision for all 40 patients. 36 patients showed significant improvement in the functioning of eustachian tube . Conclusion: After balloon dilatation , majority of the patients showed significant improvement in the eustachian tube function.Eustachian tube balloon dilation constitutes a safe and very promising treatment option for patients with Eustachian tube dysfunction based on early-outcome analysis. ETS and specifically tubomanometry appear promising as assessment tools but await validation for use in the diagnostic workup and outcome analysis after ETBD. The pathophysiologic mechanism of Eustachian tube balloon dilation remains unclear. Long-term analysis and stratification of patients are needed to better evaluate the definite value of Eustachian tube balloon dilation.