Preoperative computed tomography (CT) scan evaluation of the temporal bones in cochlear implant candidates plays a crucial role in determining candidacy and the side of implantation. The CT scans allow the surgeon to carefully review the anatomy of the inner ear and mastoid cavity in order to predict any potential difficulties or complications that may be encountered during the implant insertion. We retrospectively reviewed 50 preoperative CT scans of the temporal bone in children who have been successfully implanted. In these scans, we assessed the degree of mastoid pneumatization, cochlear anatomy and patency, size of the vestibular aqueduct, cochlear aqueduct, and internal auditory canal. We analyzed our findings and measurements and compared our results with the degree of difficulty noted in the insertion of the implant, the number of electrodes inserted in each case, and the overall complication rate. From this radiographic review, we have created a checklist for cochlear implant surgeons in order to highlight key features that need to be recognized in the temporal bone scan in preoperative evaluation of cochlear implant candidates.