Eustachian tube (ET) dysfunction plays an important role not only in the pathophysiology of various middle ear disorders, but also in predicting the outcome of the treatment. As there is no single test that assesses both the anatomic and physiological functions of the ET, a combination of tympanometry and dynamic slow motion video endoscopy may improve the sensitivity of ET function assessment.  To find out if there is any correlation between dynamic slow motion nasal video endoscopy and impedance audiometry in assessing ET function in patients with middle ear diseases.  Ours was a descriptive study performed with 106 patients attending the Ear, Nose and Throat (ENT) Outpatient Department of a tertiary care center in South India with features suggestive of middle ear disease. All patients underwent impedance audiometry and dynamic slow motion nasal video endoscopy, and were graded based on the severity of the ET pathology.  A total of 47 out of 97 patients with abnormal endoscopy findings also had abnormal impedance audiometry. The correlation was greater among the patients with higher grades of ET dysfunction. The endoscopy findings of 106 cases, when correlated with middle ear manometry, revealed that 56 cases showed complete agreement, and 50 cases showed disagreement. The nasal endoscopy results, when correlated with middle ear manometry studies by using McNemar's chi-squared (χ ) test, showed a significant association between the 2 tests (  = 0.017).  There is a significant alteration in middle ear pressure as the severity of the ET tube dysfunction increases. Impedance audiometry and nasal endoscopy provide a better measure of ET function.