The electrochemical deposition of zirconia thin films on boron-doped diamond electrodes was explored, based on the reduction of ZrOCl2. Microscopy and photoelectron spectroscopy observations suggest that the material is deposited as a thin uniform thin film over the electrode surface. Electrochemical measurements show that the electrochemical response of the clean electrode is gradually and significantly reduced as the extent of deposition is increased. The results are considered in the context of the surface attachment of biomolecules for electrochemical biosensor applications. (c) 2010 The Electrochemical Society. [DOI: 10.1149/1.3518453] All rights reserved.