Amorphous ZITO films were deposited by dc magnetron sputtering onto glass substrates from ceramic oxide targets containing Zn:In:Sn cation ratios of 1:2:1 and 1:2:1.5. The microstructure, carrier density, mobility, and resistivity of as-deposited and annealed samples were evaluated using x-ray diffraction and Hall effect measurements. The as-deposited films were amorphous and remained so after annealing at 200°C in air for up to five hours. Transmissivity of the films exceeded 80% in the visible spectral region. The minimum resistivity value (7.6×10−4 Ω-cm) was obtained from thin films deposited using the 1:2:1 composition target and a substrate temperature of 300°C.