Cochlear implant (CI) surgery is mainly based on a proper exposition and visualization of critical anatomical areas of the temporal bone, as to allow a proper positioning of all CI components and a complete and smooth insertion of the electrode array into the cochlea via the round window. Each single case must be carefully evaluated as to determine the more suitable surgical approach. This chapter focuses on the two main surgical approaches in cochlear implant (CI) surgery, the standard transmastoid, and the subtotal petrosectomy (SP). Key surgical steps as well as surgical refinements and crucial tips are summarized, emphasizing the importance of those steps that are crucial to avoid postoperative complications.