Cochlear implant (CI) surgery in the setting of an open mastoid cavity is evolving. Two strategies are commonly pursued: a staged approach, clearing the disease, closing the meatus or the external auditory canal (EAC), and reevaluating in 3 to 6 months prior to implantation, or a single-stage procedure with mastoid obliteration without EAC closure. Meatal closure is often employed in the setting of an open mastoid cavity to reduce the risk of electrode extrusion and infection. An open cavity offers the advantages of being a single-stage procedure, permitting direct surveillance for recurrent cholesteatoma, and reducing the need for repeat computed tomography scans. We describe an approach to the coverage of a CI within a dry, open mastoid cavity using an anteriorly-based postauricular pericranial flap.