A nonprogressive and conductive hearing loss in the range of 40 to 60 dB without a history of trauma or infection is highly suggestive of a congenital ossicular malformation. We analysed 34 cases of isolated congenital ossicular malformation which were confirmed through exploratory tympanotomy and were classified into nine types of anomalous patterns. Stapes footplate fixation was the most common type among the 9 anomalous patterns, which was usually bilateral. Success of the surgical treatment might depend on the stapes footplate mobility and developmental status of the oval window even though we could make a diagnosis through temporal bone computed tomography(CT).