In the present work we investigated the change of preferred crystalline orientation of indium oxide thin films prepared by ultrasonic spray technique on glass, single crystalline Si (400) and KCl single crystal substrates heated at 500°C. The structural analysis suggests that films deposited on glass and Si wafer substrates are polycrystalline with a preferred grain orientation along the (222) plane. However, films deposited on KCl single crystal substrate, exhibit preferred (400) orientation. The films deposited on KCl substrates have larger grain size than the ones deposited on the other substrates. The electrical characterization indicated that films deposited on KCl substrates have lower resistivity of 0.8×10−3Ωcm. While films prepared on glass substrates exhibit higher resistivity in the order of 33Ωcm. This discrepancy is explained in terms of oxygen diffusion from the films towards the KCl substrate.