The effect of three deformation methods (equal channel angular pressing (ECAP), multiaxial deformation (MAD), and rotary swaging (RS)) on the structure, texture, mechanical and corrosion properties of magnesium alloy WE43 (Mg-3.56%Y-2.20%Nd-0.47%Zr) was studied. Microstructure, texture, and mechanical properties were investigated by optical and transmission electron microscopy, X-ray diffraction, and tensile testing, respectively. Corrosion resistance was evaluated by a combination of mass loss and hydrogen evolution measurements, as well as electrochemical testing. To assess the effect of the various deformation methods on the biocompatibility in vitro of the alloy, hemolysis and cytotoxicity on peripheral blood cells and proliferation of multipotent mesenchymal stromal cells were evaluated. It tests showed that grain refinement in the range of ~ 0.6 - 1 μm achieved by mechanical processing is responsible for a significant improvement of mechanical properties. A notable decrease in the corrosion rate was observed after ECAP and MAD processing. MAD and ECAP enhanced alloy biocompatibility in all in vitro tests, while the effect of RS was less significant. In summary, the results obtained demonstrate that not only do the deformation methods employed improve the mechanical properties of alloy WE43, but they also increase its corrosion resistance and biocompatibility in vitro.