Highly conductive and transparent thin films of amorphous zinc indium tin oxide are prepared at room temperature by co-sputtering of zinc oxide and indium tin oxide. Cationic contents in the films are varied by adjusting the power to the sputtering targets. Optical transmission study of films showed an average transmission greater than 85% across the visible region. Maximum conductivity of 6 x 10(2) S cm(-1) is obtained for Zn/In/ Sri atomic ratio 0.4/0.4/0.2 in the film. Hall mobility strongly depends on carrier concentration and maximum mobility obtained is 18 cm(2) V(-1) S(-1) at a carrier concentration of 2.1 x 10(20) cm(-3). Optical band gap of films films varied from 3.44 eV to 3 eV with the increase of zinc content in the film while the refractive index of the films at 600 nm is about 2.0. (c) 2007 Elsevier B.V. All rights reserved.