The recent advances in the application of microscope in otological surgery have resulted in increased discovery of congenital malformation of the middle ear. It has been known that the isolated congenital malformation of the ossicle, with normal external ear, is extremely rare. The author report a case of congenital anomaly of the Incus of the left ear in a 26-year-old Korean man who came to the department of otolaryngology, Presbyterian Hospital, with a chief complaint of hearing impairment. Tympanotomy and stapedectomy with stainless wire procedure was successfully performed and the hearing was restored. The pathogenesis in embryological aspect is reviewed.