The rehabilitation of profoundly deaf patients by means of cochlear implants has become a well established form of therapy. Recently, large scale studies have pointed out a variety of surgical complications. A multiplicity of new implant types are each placing more specific demands on the surgeons. Based on the experience with about 160 cochlear implantations in total, the most suitable surgical technique for the implantation of the Combi 40 cochlear implant which has been used in 41 cases is presented. An extended retroauricular incision is made and a caudally based flap is fashioned. The implant bed is drilled 0.5-1 cm behind and above the mastoid cavity. Between the implant bed and the mastoid cavity a groove for the electrodes is drilled cranial of the implant site in the right ear and caudal in the left ear. Access to the scala tympani is gained by a promontory cochleostomy via a posterior tympanotomy of 2x3 mm. Videocontrolled microendoscopes are used to inspect the scala tympani prior to electrode insertion. Electrode insertions depths of up to 30 mm are usually achieved. The electrode and the implant are secured with ionomer-based cement. The described technique has up to now been successfully performed in 30 adults and 11 children.