Indium molybdenum oxide (IMO) films were made from an oxidized target with In2O3 and MoO3 in a weight proportion of 99:1 by using a high density plasma evaporation with the substrate maintained at room temperature. Effects of the oxygen contents of 1%-28.6% on the structural and optoelectronic properties of the IMO films have been investigated. Results revealed that the addition of oxygen showed an increase in the mobility of the IMO films. Optimized oxygen vacancies and high mobility could dominant the conducting mechanism. X-ray photoelectron spectroscopy and x-ray diffraction analyses indicated that enhanced crystalline structure improved the mobility and transmittance of the film. Uniform IMO films with resistivity of 3.56x10(-4) Omega cm and average transmittance of 85.06% over the wavelength of 450-800 nm were obtained. (C) 2004 American Vacuum Society.