This chapter provides detail description of Electric acoustic stimulation and hearing preservation: Atraumatic surgical techniques and outcome. Abstract of the chapter is given in the beginning. Chapter has 7 well illustrated diagrams and pictures. Cochlear implantation to electric acoustic stimulation (EAS), history of hearing preservation cochlear implantation, indications and criteria for EAS, defining for residual hearing for EAS, hearing preservation cochlear implant surgery, cochlear implant electrode design and hearing preservation, posterior tympanotomy, are described in detail. One table is included to highlight hearing preservation. 42 references are included at the end of the chapter to facilitate further reading.