The goal of this paper is to review the risks and complications of the cochlear implant surgery in its pre, trans and postoperative aspects, as well as possible management for their prevention and treatment. The authors also comment the complications in a series of 35 patients operated in the last four years at the University of Sao Paulo Medical School. Only experiment teams should perform the cochlear implant surgery. Although rare and susceptible to management in the majority of cases, every team working with deaf people and cochlear implants must know the complications of such kind of surgery.