Microstructuration of a protective tantalum oxide layer was investigated by the combination of substrate surface patterning with colloidal particles and electroreduction of TaF5 in ionic liquid. The formation of a two-dimensionally (2D) ordered monolayer of polystyrene particles was achieved on a square centimeter area using a facile method, which does not require additives or specific apparatus. Parameters of a previously reported protocol for tantalum electrodeposition on bare titanium were optimized to retain the integrity of the 2D ordered monolayer of polystyrene particles, and also to lead to the formation of a dense, homogeneous, adherent, and passivating structured layer of Ta2O5. (C) 2009 The Electrochemical Society. [DOI:10.1149/1.3206593] All rights reserved.