Cochlear implantation is becoming an increasingly accepted rehabilitative procedure for post lingually deafened adults. The testing, evaluation, and surgery have become standardized procedures. In this case results of two different promontory tests were contradictory. A constant voltage stimulation test was negative, while a later constant current stimulation test indicated good residual function. The CT scan accurately predicted the location of the round window remanent. In order to gain access to the cochlea, a partial labyrinthectomy was performed. Successful implantation was ultimately achieved. This implies that a previous labyrinthectomy may not be an absolute contraindication to cochlear implantation.