Twelve deaf patients with obliterated or ossified cochleas received the extracochlear version of the Vienna Cochlear Implant. Four patients, 1 of them a child, developed open speech comprehension. Obliteration of the cochlea could not always be predicted by conventional tomography of the temporal bone. Short duration of deafness, wide dynamic range, and good ability of time resolution (small temporal difference limen [TDL]) are predictors for good postoperative results. Obliteration or ossification of the cochlea per se is no contraindication to cochlear implantation.