The age at which children are receiving cochlear implants has dropped dramatically; some children now undergo surgery when less than 12 months old. Considerable feedback is required from the patient in order the set the device optimally. This can be difficult in very young children, who may be unable to provide any behavioural information. It is therefore vital that objective measures are available in order to evaluate the device and auditory function, set the programming parameters and even assess performance. This text covers cochlear implant objective measures used before, during and after surgery. It provides a handbook for clinicians detailing the many techniques used, including telemetry, averaged electrode voltages, and electrically-evoked stapedial reflexes, auditory brainstem responses, compounds action potentials, middle, late and event-related potentials. The internationally respected chapter authors from Europe and the US provide coverage of the objective measures used in several commercially available cochlear implant devices.