In this study, indium tin oxide (ITO) films were fabricated by r.f. reactive sputtering on glass substrates at room temperature. After the deposition process, the films were treated by oxygen and (30% H-2 + 70% N-2) gas mixture plasma, respectively. The effect of the plasma treatments on the electrical and optical properties of ITO films was then investigated. It was found that such parameters as the period and number of the plasma treatment had a great influence on the optoelectronic properties of the films. The property variation of the plasma treated films differed for the oxygen and the (30% H-2 + 70% N-2) gas mixtures. Some potential applications of plasma treated films are also discussed.