The lack of cristalline structure in metallic glasses suggests that no mechanical size effect could be expected. However, if the sample size decreases, a transition around 400 nm in size between deformations localized in shear band and homogeneous deformations was observed mainly on micropillars machined by FIB. But there are still a few questions which remained unanswered on elaboration process and their influence on amorphous structure with the size decreasing. This thesis deals with on a new way to characterize the size effect on the mechanical behaviour of metallic glasses. Metallic glasses thin films were elaborated by MS-PVD and mechanical samples were designed thanks to microelectronic process. Homogeneity of the amorphous structure and of the composition were determined by XRD and TEM. Elastic constant such as Young modulus and shear modulus obtained by Brillouin scattering analysis are also steady whatever the thicknesses. Nevertheless, nano indentation measures showed that Poisson ratio and Bulk modulus increase when the thin films thicknesses increase. Deformations observed on nano bending sample and imprints in nano indentation show also a transition between homogeneous deformation and deformations with shear bands. The origins of these transitions between the mechanical properties are discussed from a elastic perfectly plastic model and the Shear Transition Zone model.