Thin films consisting of a mixture of indium, gallium, zinc, and oxygen were fabricated for use as transparent conductive films for liquid crystal and/or electroluminescent displays. The thin films were produced in one step by a sputtering deposition method using mixed powder targets with different proportions of indium oxide, gallium oxide, and zinc oxide. The deposition rate of the films strongly depended on the composition of the target. X-ray photoelectron spectroscopy results revealed that mixed indium, gallium, zinc, and oxygen thin films can be prepared and their element concentration ratio is controlled by the concentration ratio of the powder target.