Transparent Sn-doped In2O3 (ITO) single-layer and ITO/Au/ITO multilayer films were deposited on glass substrates by reactive magnetron sputtering to compare the properties of the films. They were then annealed in a vacuum of 1 × 10-2 Pa at temperatures ranging from 150 to 450 oC for 20 min to determine the effect of the annealing temperature on the properties of the films. As-deposited 100 nm thick ITO films exhibit a sheet resistance of 130 Ω/□ and optical transmittance of 77% at a wavelength length of 550 nm. By inserting a 5 nm-thick Au layer in ITO/metal/ITO (IMI) films, the sheet resistance was decreased to as low as 20 Ω/□ and the optical transmittance was decreased to as little as 73% at 550 nm. Post-deposition annealing of ITO/Au/ITO films led to considerably lower electrical resistivity and higher optical transparency. In the Xray diffraction pattern, as-deposited ITO films did not show any diffraction peak, whereas as-deposited ITO/Au/ITO films have Au (222) and In2O3 (110) crystal planes. When the annealing temperature reached the 150 - 450 oC range, the both diffraction peak intensities increased significantly. A sheet resistance of 8 Ω/□ and an optical transmittance of 82% were obtained from the ITO/Au/ITO films annealed at 450 oC.