Effects of the thickness of indium films and the annealing temperature on structural, optical and electrical properties of chemically deposited CdZnS films were investigated. The diffusion process of evaporated indium was carried out by heating the sample in air at 150-550 degreesC for 1 h. X-Ray diffraction patterns of CdZnS films indicate that the minimum thickness and annealing temperature for the formation of an In2O3 layer, which acts as a barrier preventing the out-diffusion of indium and gives a high optical transmittance, are 20 nm and 350 degreesC, respectively. As the thickness of indium film and the annealing temperature increase, the conductivity of CdZnS films improves and the lowest resistivity of 0.3 Omega-cm is attained for CdZnS films with a 40 nm indium coating and annealed at 450 degreesC.