The stability of ceramic ossicular replacement prosthesis (CORP) in the middle ear was evaluated in 162 ears that had been followed for more than 18 months. The CORP extruded from 8 ears (4.9%) and was dislocated in 6 ears (3.7%). These failures were considered to be due mainly to postoperative tubal dysfunction and disease recurrence. CORP should not be used when such conditions can be anticipated.