Background. Chronic Otitis media with effusion (COME) is characterized by presence of effusion in the middle ear behind an intact tympanic membrane during 3 months or more. This study was conducted to evaluate the influence of middle ear effusion on Pneumatic Otoscopy, Otomicroscopy, Impedance Audiometry, Distortion product otoacoustic emission (DPOE) and Brainstem Electrical Response Audiometry (BERA). Material and methods. This is a prospective comparative study. Children with COME established on the basis of Otomicroscopy, complete Audiologic examination underwent tympanotomy with collection of effusion from the middle ear. Presence and character liquid were compared with the results of preoperative examinations.