High quality mono-phase MnO nanowires were successfully synthesized by vapor phase deposition on a silicon substrate. By involving the silicon into the reaction, MnO nanowires, Mn-Si oxide microwire/nanowall radial heterostructures and silicon oxide nanowires were able to be selectively obtained. The obtained MnO nanowires have a single crystal fcc structure with the average diameter of 150 nm and length up to 100 mu m. The vapor-solid (VS) mechanism was proposed as the dominant mechanism in growing the MnO nanowires. Controlled synthesis of MnO nanowires provides the possibility of exploring their potential in applications such as catalysts, battery technology and magnetic materials. (C) 2010 Elsevier B. V. All rights reserved.