A new preparation method for tin-doped indium oxide (ITO) films containing nano-scale indium tin (IT) sandwich layer(s) by the combined use of reactive and non-reactive d.c, magnetron sputtering is proposed. The film properties vary markedly with the number of IT layers and the thickness ratio m of the IT layer to the ITO layer. The lowest resistivity of a 100 nm film is 5.8 x 10(-4) Omega cm with IT layers, but 9.8 x 10(-4) Omega cm without IT layers. The transparency of the film is greater than 90% in the visible region.