text:           Involvement of the incudostapedial joint anomaly in conductive deafness.  Conclusion. The outcome of surgery depends on complexities of middle ear anomalies and definite diagnosis can only be achieved during exploratory tympanotomy. We must be aware that the pathology of the congenital ossicular anomalies is variable and careful surgery is needed for hearing improvement. Objective. This study aimed to investigate congenital ossicular malformation. Subjects and methods. Fifteen cases of ossicular anomalies without external ear malformation were studied. The anomaly of the incus-stapes complex was the most frequent. There were two cases of fused incudostapedial (IS) joint, which is an extremely rare occurrence. Case 1 was a 33-year-old man, in whom otosclerosis was suspected and exploratory tympanotomy was performed. The IS joint was fused, and the stapes was immobile. Small fenestra stapedectomy was performed. In case 2, a 52-year-old woman, otosclerosis was also suspected and exploratory tympanotomy was performed. The IS joint was fused and the incus was fixed. After the long process of the incus was cut, the stapes became mobile. However, since the incus remained immobile, it was removed and was placed on the stapes. In both cases, the hearing improved after surgery. The averaged hearing gain of 15 cases was 28.8 dB.