Cadmium-tin oxide (CTO) films with high conductivity and high transparency were prepared by rf sputtering from a CdO-SnO2 target in an Ar or Ar-O2 atmosphere. The resistivity of CTO films was 6.5×10 -4 Ω in the film thickness range of 2500-15000 Å, and the average transmission was 90% over the visible region.