The standard transmastoid facial recess approach has become the popular technique for cochlear implantation. Although this approach has been used for implantation in patients with common cavity malformations, in patients with this anomaly and severe abnormalities of the middle ear, this approach may be technically difficult and makes the facial nerve vulnerable to injury. Using a direct approach to the common cavity through the mastoid cavity, we have successfully performed cochlear implantation in 1 patient with a common cavity malformation. This transmastoid labyrinthotomy approach to the common cavity is an effective and simple technique for placing the electrode array. It minimizes the risk to the facial nerve and may decrease postoperative cerebrospinal fluid leaks.