Zinc stannate (ZnO-SnO2) thin films were deposited on ultraviolet fused silica (UVFS) substrates using filtered vacuum arc deposition (FVAD). During deposition, the substrates were at 200 and 400 °C. As-deposited films were annealed at 500 and 600 °C in Ar for 50min. The structure was determined before and after annealing using x-ray diffraction (XRD). The XRD patterns of all ZnO-SnO2 thin films had an amorphous structure. The average optical transmission of the film in the visible spectrum was>80% and was affected by annealing. The films' optical constants in the 250-989nm wavelength range were determined by variable angle spectroscopic ellipsometry (VASE). The refractive indexes of as-deposited and annealed films were in the ranges 1.95-2.35 and 2.0-2.32, respectively. The extinction coefficients of as-deposited annealed films were in the same range, approximately 0-0.5. However, in the UV range (<450nm) the extinction coefficient values decreased significantly for annealed films. The optical energy band gap (Eg) was determined by the dependence of the absorption coefficient on the photon energy at short wavelengths. It varied between 3.65 and 3.72eV for annealed films as a function of deposition pressure. Although the lowest electrical resistivity of zinc stannate films obtained for as-deposited films on 400 °C heated substrates, using 0.93Pa oxygen pressure, was 1.08 × 10-2Ωcm, highly resistive films (>105Ωcm) were obtained by annealing.