Lithium tantalate (LiTaO3) thin films with submicron thickness were prepared by the "pyrosol" process based on the thermal decomposition on a heated substrate of an aerosol obtained by ultrasonic spraying. The crystalline orientations of the films versus different experimental parameters, like the substrate nature and the deposition temperature, were studied. Crystalline structure analysis of deposited materials showed that LiTaO3 films crystallized successfully with single orientation on c-oriented sapphire substrates, without using post-thermal annealing treatment.