In this study, the capability of producing thin-walled high strength fine-grained magnesium tubes using the radial–backward extrusion process as a severe plastic deformation (SPD) technique was investigated. The main objective of this research was to evaluate the feasibility of manufacturing high-strength magnesium tubes with a refined microstructure through the application of large accumulated plastic strains. Experimental investigations included tensile testing, Vickers microhardness measurements, metallographic observations, and fracture surface analysis using scanning electron microscopy (SEM). In addition, finite element simulation was performed using DEFORM software to analyze material flow behavior and plastic strain distribution during the process. The results indicated that the application of severe plastic deformation during the process led to dynamic recrystallization and a significant reduction in grain size from approximately 130 μm in the initial material to nearly 6 μm in the final product. The effective plastic strain increased up to about 3.9, resulting in considerable improvement in the mechanical properties of the extruded samples. Yield strength and ultimate tensile strength, as well as hardness, increased significantly compared with the initial condition, while the fracture behavior changed from brittle intergranular fracture to a ductile fracture characterized by fine and uniformly distributed dimples. The hardness and strain distributions also demonstrated that the homogeneity of properties along the tube length was greater than that across the wall thickness. Furthermore, the investigation of process parameters showed that increasing the friction coefficient and decreasing the final tube thickness led to higher plastic strain levels and enhanced grain refinement. Keywords: Radial-indirect