Idiopathic blue eardrum or idiopathic hemotympanum that contains a brownish secretion in the middle ear is a chronic condition in which the entire drum is of a distinct blue color and in which étiologie factors such as cranial injury, bleeding from nasopharynx, operative injury, barotrauma, tumors, hemorrhagic diathesis and anomalies have been ruled out. Although many authors have reported the blue eardrum since it was first described ‘blue drum membrane’ by Shambaugh (1929), the pathogenesis of this disease is still controversial, as it is still undetermined whether it is a variant from of otitis media with effusion or a quite independent clinical entity. In the present study, we analysed 15 cases of idiopathic blue eardrum which had been treated through mastoidectomy with ventilation tube insertion to evaluate the relationship between the maintained time of ventilation tube and the drum finding, and confirmed that the earlier the ventilation tube was removed, the higher the possibility of eardrum troubles such as retraction, adhesion, and cholesteatoma was. This result suggested that the eustachian tube dysfunction is a consistant finding in idiopathic blue eardrum.