Cochlear implantation (CI) is an established technique for enabling speech perception in patients suffering from severe bilateral sensorineural hearing loss (SNHL). Thorough preoperative radiological assessment is essential for correctly evaluating the indication for surgery and safely performing cochlear implantation. CT and conventional and functional MRI are available for radiological assessment. Therefore, knowledge of the most frequent congenital syndromal, non-syndromal, and acquired malformations of inner ear structures is fundamental. This article provides information about imaging techniques prior to CI and relevant malformations of the inner ear. Safety aspects for patients with a cochlear implant undergoing MR imaging are also discussed.